Themes: Handle apps using "original-package" tag

Before this patch the themes code assumed the pkgName from PackageInfo was equal to the
manifest value. This is not the case however for upgraded system apps that have gone
through a pkg-name change. For example, Trebuchet was "com.android.launcher3" and now
it is "com.cyanogenmod.trebuchet". If the device had wiped data then PM would use the new
pkg-name, but if the system apps were being upgraded then PM would use the old name which is
now different from the manifest name.

Change-Id: Ie7eb1b4e17899d1055535dc890d4f7a7bca9a98a
Cleanup app->{theme1,theme2...} mapping on uninstall

Change-Id: I24b43e8817db1927d5b43fcf7ad3340269d046ea
Themes: remove unused code

Change-Id: I5ee8de962c40ddc5fcfbbc0332a9e389223e716c
Themes: Delete icon resources during uninstall

Change-Id: Icf247642f9d246c8826f3394f873e4b434ad2b3f