All flights with a student are forced to have the Student Trg sequence

[LukeTowers]

Currently all flights with a student glider pilot are automatically forced to have the Student Trg sequence, even when that sequence doesn't make sense (i.e. student is getting a ride in the tow plane, student is with a pilot that is not an instructor, etc). While you can go back to the flight and edit it after the fact it would be better to make the following changes:

• Narrow the cases that the autodetection of student pilots kicks in. For example, this feature should only trigger when the student pilot is in a glider, and the PIC is an instructor
• Make it an opt-in change instead of an opt-out change. A window should popup saying something along the lines of "PILOT X is a student and PILOT Y is an instructor, you mean to make this flight a Student Trg flight?" Options would be "Keep SEQUENCE Z" and "Change to Student Trg"