[TIMOB-14980] Android Build: Package and sign app

* package ** package assets (aapt package) ** only package internal Titanium jars that are required based on the AST parsing (TIMOB-6845 Android: Ti should include only the used features/libs into a new app) ** create unsigned apk (basically a zip file) *** if production, strip debugging symbols (TIMOB-2363 Android: Strip debugging symbols from JARs when building for production) *** if classes.dex (returned by dex command) does not exist in apk or has been updated, then write the classes.dex to the apk file *** for each abi, add the native/libs//* to the apk file (TIMOB-14242 Android: x86 libs not included in production APK) ** run jarsigner on unsigned apk *** pass in the store password and key password (if exists) (TIMOB-6423 builder.py should accept an alias password) ** zipalign signed apk