Initial dependencies for passkey work

[melissaahn]

Summary

This brings in the necessary dependencies (that I know of so far) into the common build.gradle, along with a few other changes.

• androidx.credentials:credentials and androidx.credentials:credentials-play-services-auth are the [Credential Manager] (https://developer.android.com/jetpack/androidx/releases/credentials) dependencies needed to interact with Google Password Manager and other 3P passkey providers. The most stable version is a beta version, so I expect the version to change a few times in the next few months.
  • I'll create actual variables to hold the dependency versions in a future PR (before the feature branch gets merged into dev).
• androidx.lifecycle:lifecycle-runtime-ktx in order to make use of the lifecycle scope. The main methods from CredMan need to run in a coroutine, and the lifecycle scope fits what we need there.
• CredMan documentation suggests adding directives to the proguard-rules.pro file to not optimize androidx.credentials.playservices right away.
• Changes to the gradle, kotlin, and compileSdk versions are expected to be merged directly into dev with separate PRs. For now this means that all common checks are probably going to fail.

I was able to make some test calls with CredMan to create a demo passkey and sign a challenge with the passkey.

[melissaahn]

Based on Dome's suggestion, I think it would be best to close this PR for now and wait for the kotlin and gradle PRs to be created/merged in first. I'll then create a set of PRs for all libraries + android-complete that updates with the passkey dependencies.