(Android) Migrate instrumentation support lib to androidx libs

[d4vidi]

• This is a breaking change, requiring a major version upgrade
• This change has been discussed in issue Migrate to Android jetpack (androidx) #1173 and the solution has been agreed upon with maintainers.

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Description:

With respect to #1173 --
This is phase 1 of a 2-phase procedure towards fully migrating:

1. Switch to androidx and provide a migration guide, bundled with the regeneration of the JS Espresso-contract classes based on this androidx test repo and tag
2. Introduce the androidx test repo as a submodule and take the contracts from there, similar to what we already do with EarlGrey.

Reasons not to do step 2 right now are that this change is already pretty big as-is, and that step-2 will not be breaking in the users' perspective.

[d4vidi]

@LeoNatan @rotemmiz I need you guys to have a look at this - go over the docs, in the very least.

[lucasnlm]

Is there any new Google link to be used here?

[d4vidi]

Hey @lucasnlm, not sure I understand the question. This is a link to raw content of this repo: https://github.com/android/android-test

[d4vidi]

Update: I've decided to skip part 2 of this upgrade, as I don't see too much point in adding the submodule unless we effectively compile it along with Detox.
Currently the status is that the generator grabs the code from google's android-test repo on github from a tag that is perfectly aligned with the versions we use for the testing artifacts we defined as dependencies in our build.gradle. I find this to be suitable for what we need. See my inline comment for more details: https://github.com/wix/Detox/blob/master/detox/android/detox/build.gradle#L78