libs: Build against the correct anvill version (lifting-bits#745)

Rework Docker Image build (lifting-bits#741)

* Try reworking Docker image

* Fix some old behavior for building abi libraries

I don't think the result is actually usable...

* Remove most Python2 references

Still left some references to python2 for helper scripts since they
aren't tested (afaik) in CI

* Fix CI

* Remove old CMakeLists.txt and remove support for old TRAILOFBITS_LIBRARIES method of building

* Update README

Remove most Python2 references (lifting-bits#742)

* Remove most Python2 references

Still left some references to python2 for helper scripts since they
aren't tested (afaik) in CI

* Fix CI

Fix bad LoadInst compat for LLVM 11 (lifting-bits#739)

* Fix bad LoadInst compat for LLVM 11

* Add lifter smoketest. Just check for 0 return

* Use macos 10.15 CI runner

Fix anvill install target usage (lifting-bits#736)

Anvill now installs unversioned target

Add rpm dependency needed by downstream (lifting-bits#734)

Limit MacOS CI Runners (lifting-bits#733)

Limit MacOS CI runners due to organizational limits

Remove Python2 from pushed Docker images (lifting-bits#731)

Had to rename the directory where the Python 3 module is installed so
that we could hard-code the PYTHONPATH to it, e.g. `lib/python3.6` ->
`lib/python3` on Ubuntu 18.04 with default Python version installed by
`apt install python3` or `lib/python3.8` -> `lib/python3` for Ubuntu
20.04.

Support LLVM 11 (lifting-bits#729)

* Add guards based on LLVM version for 11 compatibility

* Use remill LLVM 11 compat headers

* CI support for LLVM 11

vcpkg: Support Windows and arm64 (lifting-bits#726)

* Fixes and updates for McSema to build on Windows

* Enable C CXX ASM languages from beginning

Workaround for issue after finding Clang using Clang's own CMake
find-scripts

* Support aarch64 and Windows release triplets

* Conditional link to remill_settings for new vcpkg build