Remove .mo files from Git, they are generated.

.mo files are the compiled .po translation files and should be
generated during the build process.
Move translation files
Generate .mo translation files during build process.
Add gettext translation managing tasks.
Add task for re-merging the .po files with the master .pot file.
Run xgettext on our sources and re-generate the .pot master file.
Update all the .po files with the master .pot file.
Fix po headers of .po files
Start translation guide