* feat: Build Crashpad via a CMake submodule
* feat: Integrate the Crashpad Client
* get crashpad handler working
* build handler with tests
* integrate msgpack, and finish crashpad backend
* add path handling methods for windows
* make crashpad work on windows
* add options when applying scope to event, avoid redundant callbacks,
and correctly add breadcrumbs in non-crashpad mode as well.
* use a different msgpack library and vendor it
* rm gitattributes; windows should use native line endings
* update crashpad submodule
* review feedback and leak fixes
* clean up current_exe and path_dir handling, add a test
* fix some leaks in the crashpad backend and
around raw envelopes and breadcrumbs
* correctly clone in path_dir on windows as well
* move handler path handling into crashpad backend
This adds support for libunwindstack based unwinding for Android.
Currently this only builds these things through cmake which is likely what we're going
to use going forward.