* Add flight level field to PIREP field closes#401
* Default value for distance 0 closes#400
* Block airline deletion if assets exist #367
* Formatting
* Move some of the base exception classes
* Fix skin references to use settings table
* Set default for theme name if setting is wrong
- flight ident now use this format: VA IATA(if empty ICAO) + Flight Number + - + Flight Code (without C) + - + Flight Leg (without L)
- added function __trans_choice in helpers.php for translation
- fixed error in flight edit/insert panel not showing/inserting Tuesday in days
- fixed an error occurring when metar retrieved is empty
- edited now-ui-kit.css to align login fields correctly
- added /public/assets/frontend/js/core/jquery-3.3.1.min.js to fix a missed resource error in authentication pages
- added translations file for en and it locales
- translated all the frontend templates