Remove dependency on doc versions - #29906

See elastic/elasticsearch#38254

Using the `version` parameter to implement optimistic concurrency is not going to be supported in 7.0, so we need to replace our usage of document version with the new `_seq_no` and `_primary_term` parameters. These fields are returned in the same way that `_version` was returned on all read/write requests except for search, where it needs to be requested by sending `seq_no_primary_term: true` in the body of the search request. These parameters are sent back to Elasticsearch on write requests with the `if_seq_no` and `if_primary_term` parameters, and are functionally equivalent to sending a `version` in a write request before elastic/elasticsearch#38254.

To make these updates I searched the code base for uses of a `version` and `_version`, then triaged each usage, so I'm fairly confident that I got everything but it's possible something slipped through the cracks, so if you know of any usage of the document version field please help me out by double checking that I converted it.

- [x] **Saved Objects**:  @elastic/kibana-platform, @elastic/es-security - for BWC and ergonomics the `version` provided by the Saved Objects client/API was not removed, it was converted from a number to a string whose value is `base64(json([_seq_no, _primary_term]))`. This allows the Saved Objects API and its consumers to remain mostly unmodified, as long as the underlying value in the version field is irrelevant. This was the case for all usages in Kibana, only thing that needed updating was tests and TS types.

- [x] **Reporting/esqueue**: @joelgriffith, @tsullivan - the version parameter was used here specifically for implementing optimistic concurrency, and since its usage was contained within the esqueue module I just updated it to use the new `_seq_no` and `_primary_term` fields.

- [x] **Task Manager**: @tsullivan @njd5475 - Like esqueue this module uses version for optimistic concurrency but the usage is contained with the module so I just updated it to use, store, and request the `_seq_no` and `_primary_term` fields.

- [ ] **ML**: @elastic/ml-ui - Best I could tell the only "version" in the ML code refers to the stack version, elastic@077245f

- [ ] **Beats CM**: @elastic/beats - Looks like the references to `_version` in the code is only in the types but not in the code itself. I updated the types to use `_seq_no` and `_primary_term`, and their camelCase equivalents where appropriate. I did find a method that used one of the types referencing version but when investigating its usage it seemed the only consumer of that method was itself so i removed it. elastic@52d890f

- [x] **Spaces (tests)**: @elastic/kibana-security - The spaces test helpers use saved objects with versions in a number of places, so I updated them to use the new string versions where the version was predictable, and removed the assertion on version where it wasn't. We test the version in the saved objects code so this should be fine.

Backports the following commits to 6.x:
 - Remove dependency on doc versions  (#29906)

) (#32938)

Backports the following commits to 6.7:
 - [Infra UI] Adapt settings ui to saved object version type change (#30082) (#29622)

Caused by backport of #29906 to `6.x`.

See elastic/elasticsearch#38254

Using the `version` parameter to implement optimistic concurrency is not going to be supported in 7.0, so we need to replace our usage of document version with the new `_seq_no` and `_primary_term` parameters. These fields are returned in the same way that `_version` was returned on all read/write requests except for search, where it needs to be requested by sending `seq_no_primary_term: true` in the body of the search request. These parameters are sent back to Elasticsearch on write requests with the `if_seq_no` and `if_primary_term` parameters, and are functionally equivalent to sending a `version` in a write request before elastic/elasticsearch#38254.

To make these updates I searched the code base for uses of a `version` and `_version`, then triaged each usage, so I'm fairly confident that I got everything but it's possible something slipped through the cracks, so if you know of any usage of the document version field please help me out by double checking that I converted it.

- [x] **Saved Objects**:  @elastic/kibana-platform, @elastic/es-security - for BWC and ergonomics the `version` provided by the Saved Objects client/API was not removed, it was converted from a number to a string whose value is `base64(json([_seq_no, _primary_term]))`. This allows the Saved Objects API and its consumers to remain mostly unmodified, as long as the underlying value in the version field is irrelevant. This was the case for all usages in Kibana, only thing that needed updating was tests and TS types.

- [x] **Reporting/esqueue**: @joelgriffith, @tsullivan - the version parameter was used here specifically for implementing optimistic concurrency, and since its usage was contained within the esqueue module I just updated it to use the new `_seq_no` and `_primary_term` fields.

- [x] **Task Manager**: @tsullivan @njd5475 - Like esqueue this module uses version for optimistic concurrency but the usage is contained with the module so I just updated it to use, store, and request the `_seq_no` and `_primary_term` fields.

- [ ] **ML**: @elastic/ml-ui - Best I could tell the only "version" in the ML code refers to the stack version, elastic@077245f

- [ ] **Beats CM**: @elastic/beats - Looks like the references to `_version` in the code is only in the types but not in the code itself. I updated the types to use `_seq_no` and `_primary_term`, and their camelCase equivalents where appropriate. I did find a method that used one of the types referencing version but when investigating its usage it seemed the only consumer of that method was itself so i removed it. elastic@52d890f

- [x] **Spaces (tests)**: @elastic/kibana-security - The spaces test helpers use saved objects with versions in a number of places, so I updated them to use the new string versions where the version was predictable, and removed the assertion on version where it wasn't. We test the version in the saved objects code so this should be fine.