Temporary commit --

This commit adds the intro and initiation day fields to program type. Timings for intro are taken when program is proposed and announced.

Things which do not work --
1. Overlap logic for program is broken.
2. Following functions broken for residential programs and programs with intro -
2a. if_program_announced!
2b. teachers_connected_for_timing
2c. update_teacher_schedule_timing_str