Include onboarding/start-up translations in localized builds

With #29994 (moved) and #30015 (moved) done we can try providing localization for everything Tor Browser for Android related as it is contained in the torbrowser_strings.dtd file. This comprises both onboarding and bootstrap/bridge panel strings.

The idea would be to add that file/those strings per locale during the repacking step in our tor-browser-build build script.