Added l10n for message details

This was already in PR #1309 that was closed by the author.

Added the 4 missing strings for translation. There are indeed languages that don't use the words SMS and MMS...
Removed `toUpperCase()` to leave this up to the translators.

I tended to move SMS, MMS and PUSH at top of `strings.xml` as these are some main strings, but ConversationFragment is the only place they are used standing alone.