implement getting Main Activity from an Activity alias on Android

[andresesfm]

Summary:

Android Manifests might contain Activity aliases: https://developer.android.com/guide/topics/manifest/activity-alias-element. This allows mapping activity paths. Such aliases might contain <intent-filter>s no different from regular activities.

Test Plan:

Unit Test have been added.

In an Android project.
Create an activity and an activity-alias.
Make the activity alias point to the actual activity.
The alias should have the launcher category and main action. (Making it the main activity)
Expected: running react-native android should launch as expected on the device

Checklist

• Documentation is up to date to reflect these changes.
• Follows commit message convention described in CONTRIBUTING.md

[thymikee]

@cortinico would you mind giving this a review? Seems fine on my end, but I haven't used aliases yet, so I don't know the broader context or consequences of supporting that.

[cortinico]

I have to mention that I'm not a huge fan of this. It adds maintenance cost cli-platform-android for a very edge case feature. Users could still configure this on their end if they're using activity-alias