Linux desktop support - breakpad

[vaind]

closes #694, replaces #699 and #733

This implements the linux crash support using the breakpad handler. Issue samples:

• https://sentry.io/organizations/sentry-sdks/issues/3257750661/events/c5203eaef44249bcf360d394368e2583/?project=5439417
• https://sentry.io/organizations/sentry-sdks/issues/3262191687/events/54ee8914604b4210175ccc3f10f655cf/?project=5439417

TODOs

• symbol upload
• integration test

[bruno-garcia]

Unity on Android (IIRC) now uses the extension file.sym.so and I believe @bitsandfoxes is relying on it to run Sentry CLI on the root of a dir and pick all the right files.

Perhaps we could rely on the same bahavior if we can control the extension we use here

Suggested change

	package-dev/**/*.full
	package-dev/**/*.sym.so

[vaind]

rather ".so.debug" - that's what this answer says is the corresponding filename for "full lib with debug symbols" - https://answers.unity.com/questions/1634142/libil2cppsym-libil2cppsodebug-libunitysymso-what-s-1.html

[vaind]

or maybe not, this says something else... https://docs.unity3d.com/2020.3/Documentation/Manual/android-symbols.html

[vaind]

I've made an android build and seems like ".dbg.so" is the corresponding extension (i.e. full unstripped lib) Unity uses in Android builds:

[bruno-garcia]

@Swatinem is this the intended way for us to bundle Sentry native?