test the locales for Android with a githook after updating from transifex

We need to test the correct escaping of the files at https://git.torproject.org/translation.git on the branch tba-torbrowserstringsdtd (only on that branch!)

The files on that branch are used to localize the Android client of the Tor Browser and don't comply with the standards for dtd files. Thus, we need to check on them after updates come from transifex, and before we attempt to build.

Ideally we can produce a list of the corrections, so we can update it on the transifex platform and slowly weed out the errors.

We could reuse this githook for other components eventually, so it would be nice to have some sort of reusable parts:

• import last translations from transifex
• run something
• upload results to transifex?
• mail or submit results somehow

The script that we can use as a base is at https://trac.torproject.org/projects/tor/ticket/30054#comment:9

the rules at https://developer.android.com/guide/topics/resources/string-resource#FormattingAndStyling may not be all needed, as for example it can be that ' does not break the build.