…#4421)

## Explanation
Fixes #4389
Fixes #4407

This PR "future-proofs" the learner analytics logging infrastructure by:
- Introducing separate event names that should be more understandable to data analysts than used in the Kenya version of the app (though compatibility is still kept with existing Kenya logged metrics by means of a separate implementation used only in that build of the app).
- Logging a new ``event_type`` parameter that contains the actual proto integer of the event rather than just logging a string representation (so that we can rename both the events in code, and the corresponding strings logged to Firebase). The event names, at this point, act as a nice point-of-reference while analyzing events but are no longer meant to be the primary identifying keys for events (``event_type`` should be used for this purpose, instead).
- The device's Android SDK version, the app's version name, and the app's version code are now logged with all events for better event dimension slicing and analysis.
- Effort is now made to ensure event names don't exceed 40 characters (Firebase's limit) to help avoid events being potentially rejected during upload.

Specifics about tests and exemptions:
- ``EventTypeToHumanReadableNameConverter`` is exempted from tests since it's an interface.
- ``KenyaAlphaEventTypeToHumanReadableNameConverterImpl`` is exempted from tests since it's temporary, and its values are at least indirectly tested through ``KenyaAlphaEventBundleCreatorTest``.
- ``KenyaAlphaEventBundleCreatorTest`` was added as a fork of ``EventBundleCreatorTest`` to ensure the existing Kenya-specific event names are properly logged, but it will be removed in the future (as tracked by #4419). Note that this suite wasn't updated to verify the new fields like ``EventBundleCreatorTest`` was.
- A BUILD.bazel file was added for the existing logging/firebase and logging/performancemetrics tests since one was added for the tests under logging/ (and subpackages must also have BUILD files if parent packages do).

## Essential Checklist
- [x] The PR title and explanation each start with "Fix #bugnum: " (If this PR fixes part of an issue, prefix the title with "Fix part of #bugnum: ...".)
- [x] Any changes to [scripts/assets](https://github.com/oppia/oppia-android/tree/develop/scripts/assets) files have their rationale included in the PR explanation.
- [x] The PR follows the [style guide](https://github.com/oppia/oppia-android/wiki/Coding-style-guide).
- [x] The PR does not contain any unnecessary code changes from Android Studio ([reference](https://github.com/oppia/oppia-android/wiki/Guidance-on-submitting-a-PR#undo-unnecessary-changes)).
- [x] The PR is made from a branch that's **not** called "develop" and is up-to-date with "develop".
- [x] The PR is **assigned** to the appropriate reviewers ([reference](https://github.com/oppia/oppia-android/wiki/Guidance-on-submitting-a-PR#clarification-regarding-assignees-and-reviewers-section)).

## For UI-specific PRs only
N/A -- This is a metrics infrastructure change that will have zero effect on the UI (except maybe how events are displayed in the developer options menu, but that's not important to include here since it isn't end user-facing).

Commits:

* Create dedicated alpha application component.

This simplifies application component management significantly and
allows individual build flavors to have their own unique module lists.

* Add beta & GA update notices.

This also introduces dedicated beta & GA build flavors which is a
necessary prerequisite.

It also introduces an extra beta, alpha, and dev mode labels for the splash
screen (the latter 2 were extra) with 2 second minimum wait timers for
beta and alpha to ensure they are seen. A 5-second safety timer was
added to ensure the splash screen can always be passed even if something
goes wrong at the domain level (since there are now quite a few moving
pieces to determine the user's current onboarding state).

* Add build tests for the new beta & GA flavors.

* Add Kenya study-specific alpha build flavor.

This new build flavor automatically enables the study-specific learner
study feature flag.

* Future-proof metrics infrastructure.

This is mainly done by:
1. Logging an immutable event type for each event and de-coupling the
event names so that the latter can be changed over time to improve event
management quality-of-life.

2. Logging the Android SDK version, app version name, and app version
code with each event.

3. Ensuring the existing Kenya-specific alpha versions of the app
continue to use their existing event names so that historical data can
be matched (since those queries rely on event names rather than this new
event type).

* Fix broken test per earlier changes.

* Fix general broken tests & builds.

Tests broken due to changes to the app startup experience haven't yet
been fixed.

* Lint fixes.

* First part of adding tests for GA notices.

There's a bunch left to do here, this is mainly needed so that I can
transfer changes to a different machine.

* Update TransformAndroidManifestTest.kt

Correct typos.

* Fix tests & static checks.

This also removes temporary debug code and TODOs, and finishes the tests
for SplashActivity.

* Fix & add testing.

* Static check fixes + missing tests.

* Post-merge fixes.

* Test fixes.

* Fix failing tests.

* Fix Gradle test.

* Post-merge fixes.

* Follow-up adjustments after self-review.