fix(android): can't set versionCode in manifest as of 9.0.0

[jquick-axway]

JIRA:
https://jira.appcelerator.org/browse/TIMOB-27705

Note 1:
This issue was never in a release version. Was caught before release.
Regression caused by changing build system from "ant" to "gradle".

Note 2:
Android gradle build system ignores "versionCode" and "versionName" set in "AndroidManfiest.xml". This is by Google's design. You are expected to set these settings in the "build.gradle" file instead. This PR maintains backward compatibility by reading these 2 version settings in the "tiapp.xml" and "./platform/android/AndroidManifest.xml" and writing them to the generated "build.gradle" file.

Note 3:
Titanium app developer can also set "versionCode" and "versionName" via their own "./platform/android/build.gradle" file. This will take priority over the Titanium generated "build.gradle" file.

---

Test:

1. Create a "Classic" Titanium app project.
2. Set up the "tiapp.xml" file with the below.
3. Build for Android.
4. Go to folder: ./build/android/app/build/intermediates/merged_manifests/debug
5. Open the "AndroidManfiest.xml" file.
6. Verify android:versionCode is set to 5.
7. Copy the below "build.gradle" content to project folder ./platform/android.
8. Build for Android.
9. Go to folder: ./build/android/app/build/intermediates/merged_manifests/debug
10. Verify "AndroidManifest.xml" file's android:versionCode is set to 7.

tiapp.xml

<?xml version="1.0" encoding="UTF-8"?>
<ti:app xmlns:ti="http://ti.appcelerator.org">
	<android xmlns:android="http://schemas.android.com/apk/res/android">
		<manifest android:versionCode="5"/>
	</android>
</ti:app>

./platform/android/build.gradle

android {
	defaultConfig {
		versionCode 7
	}
}

[build]

	Messages
📖	💾 Here's the generated SDK zipfile.
📖	✊ The commits in this PR match our conventions! Feel free to Rebase and Merge this PR when ready.
📖	✅ All tests are passing Nice one! All 6550 tests are passing. (There are 700 skipped tests not included in that total)

Generated by 🚫 dangerJS against 04283b4

[lokeshchdhry]

FR Passed.

Studio Ver: 5.1.4.201909061933
SDK Ver: 9.0.0 local build
OS Ver: 10.14.5
Xcode Ver: Xcode 11.3
Appc NPM: 4.2.15
Appc CLI: 7.1.2
Daemon Ver: 1.1.3
Ti CLI Ver: 5.2.2
Alloy Ver: 1.14.4
Node Ver: 12.13.1
NPM Ver: 6.12.1
Java Ver: 11.0.1
Android Devices: ⇨ google Pixel (Android 10)