feat: translation set up

Add column language to user with default en value.
Update validation of user to allow only en and cs.
Add initial application.<lang>.yml files.
Setup usage of locale based on user's settings.
Added language configuration into user form.
Feat: Translation of calendar

Continuous work on translation, included translation
of calendar. Also cleared today and clear buttons.
Fix: remove of debugging alert
Fix: update tests to work

tests are updated to work, needed to add language attr.
Feat: continue with translation, entries done.
Feat: continue with translations, views completed
Feat: translations finished

Added translatons of messages generated by controllers.
Changed "must be admin" message to alert level to be
consistent with the rest of the app.
Fix: enhancement of namespacing and small fixes.
Fix: addition of translations for model text.

TBA: Validation messages needs to be translated.
     Specifically the name of affected attribute,
     message itself is translated correctly.
Merge pull request #3 from eballance/translations

feat: translation set up