LcfTrans translations back into the game from external file.

[rygos]

With LcfTrans strings can be extracted from the game files.
It would be nice if these strings can be loaded with external (!) Language files with the player.
Just think about community translations =)

The initial idea came from Ghabry.

Not sure if a dupe of #797, but I vote for this approach with tinygettext from liblcf 👍.

Note this is not the same as updating the game files, which is different and unlikely to get implemented because loading from PO files provides the same functionality in practice.

This is already implemented in #2287. For a rough guide check this community lcftrans translation guide.