More improved Android support

Hi. I understand that this doesn't apply to the Trisquel distro, but I'm interested in building Abrowser for Android. Most likely I will personally build apk's. Therefore, I made some changes so that the version for Android had connection to the desktop version, and didn't builds like Fennec (almost unchanged). The changes were modular, so you can always remove them without affecting the process of source code patching. Сhanges are associated with telemetry removal and branding change (P.S: xxxhdpi app icon turned out to be in poor resolution, since I didn't find the svg for Abrowser app icon. If there is such a svg, I can generate xxhdpi and xxxhdpi app icon again). I tested all the changes and successfully build Android version of Abrowser. My mozconfig for example:

export MOZ_INSTALL_TRACKING=
export MOZ_NATIVE_DEVICES=
ac_add_options --enable-application=mobile/android
ac_add_options --target=arm-linux-androideabi

ac_add_options --with-android-sdk="$HOME/.mozbuild/android-sdk-linux"
ac_add_options --with-android-ndk="$HOME/.mozbuild/android-ndk-r15c"
mk_add_options MOZ_OBJDIR=./objdir-droid

ac_add_options --enable-official-branding
ac_add_options --with-distribution-id=org.gnu
ac_add_options --disable-elf-hack
ac_add_options --enable-warnings-as-errors
ac_add_options --enable-dump-painting
ac_add_options --with-ccache