Help building microg / improve documentation request

I am trying to build microg with some modifications, and the [wiki says](https://github.com/microg/GmsCore/wiki/Building) to run ./gradlew build.
This fails with a bunch of linter excepitons, and I can't figure out how to disable the linter.

I've also looked at the microg github actions, and it runs `./gradlew assembleRelease / assembleDebug`. This works, but produces a lot of different outputs,
```
ls play-services-core/build/outputs/apk
hmsDefault hmsHuawei hmsUser mapboxDefault mapboxHuawei mapboxUser vtmDefault vtmHuawei vtmUser
```
And there is no documentation about which build is the one I want, I couldn't find what mapbox is, and the wiki doesn't talks at all about the `vending` apk.

I've also seen the (the revanced fork's CI)[https://github.com/ReVanced/GmsCore/blob/main/.github/workflows/release.yml] use this command: `./gradlew --no-daemon :play-services-core:assembleMapboxDefault :play-services-core:assembleMapboxHuawei`

So my questions are:
- What is the way developers build and test microg?
- What commands get run to produce the artifacts published to github releases?
- If I compile the vending apk too, does it need to be signed as well?

Start with the wiki's Building page and compare its ./gradlew build instructions with the commands shown in the GitHub Actions workflow and .github/workflows/release.yml from the referenced fork. Document the developer build and test steps, how release artifacts map to the listed variants, what mapbox and vending represent, and whether vending requires signing.

Written by the indexing model from the issue text.