Update the translations and delete unneeded files

--HG--
branch : 1.1-dev
rename : wger/workout_manager/settings_global.py => wger/settings_global.py
Add an alt attribute to image tags

--HG--
branch : 1.1-dev
Add test to delete and edit a workout

--HG--
branch : 1.1-dev
Add link to user preferences on main navigation bar

--HG--
branch : 1.1-dev
Add more exercise descriptions

--HG--
branch : 1.1-dev
Add a placeholder to the exercise search box, make it wider

--HG--
branch : 1.1-dev