Reverted bug introduced when underscorifying
Fixed availability filter in map of rooms

* Fixed the RoomBookingAvailabilitySearchRooms service
* Fixed default datetimes in the filter
* Extracted Room.is_available filter into a method
* Replaced legacy datepicker with jQuery one
* Usability improved for dates selection
* Template cleaned up a bit
* Removed unused mixin and helper
jQuery datepicker icon disabled on disabled input
Fixed videoconference and webcast filters in map
Post-WIP fixes