Disable translation processes we currently don't use

- Disable transifex process
- Disable removal of unfinished tags
Fix translation sprintf and qt string formats

Some translations had non-matching formats, the update-translations
script would normally remove those and set it to "unfinished".
However, since those are fairly trivial to fix, those have been
manually corrected before doing a cleanup run with the update script.
Clean up all locale .ts files

Used the new update-translations.py script to clean up all
locale files. Unlike bitcoin/bitcoin, we're keeping the
unfinished translation tags in place as long as we have
manual translations (whereas bitcoin uses transifex)