Add variants of put and post requests (#1)

This includes `patch` calls with token and `put` with an array of dictionaries.

Conform to Sendable protocol to enable concurrency

This is breaking change, only available in version 4+.

Consume recently extracted network helper

New methods, underlying functions no longer public

Remove argument aliases from method signatures

It is considered a good practice to use named arguments even though this
makes method invocations a bit more wordy.
Also, forced unwrapping has been removed from the URL arguments as this
was simply a coding mistake.

Update signatures to make `token` last parameter

This is for consistency and to potentially make it easier to make tokens
optional in the future.

Change signature of DELETE handler to only be used with empty response