[NUOPEN-6][Shared dev] Daily rate with fixed start time: create a reservation

[joaquinco]

Note

• Add Instrument#fixed_start_time boolean to tell if daily reservations should start at the beginning of the day
• Add system tests for instrument setting the attribute and reservation creation
• Hide start and end times from reservation form
• Don't render Start time availability table if fixed_start_time is on

The form component containing times and duration looks weird as it is because there's a lot of empty spacing. I will work on this after wrapping up the most important changes

Upcomming PRs will cover schedule rules, editing and moving reservations

Screenshots

[LeticiaErrandonea]

I wonder if the name should be different. We have the help text in the form but the label is "Fixed Start Time" which is not so self explanatory to me. Is the same for the field in the DB. Maybe something like "start_reservations_at_midnight"?

[joaquinco]

@LeticiaErrandonea What about reservation_start_time_disabled or just start_time_disabled?

[LeticiaErrandonea]

I think unrelated specs are failing