Log Experience Sampling Trigger

[casaout]

Users can answer experience sampling pop-ups that are automatically triggered (within active hours #332) or manually triggered.

In the experience_sampling_responses table, we are currently NOT logging this:

• add a column trigger to the experience_sampling_responses table
• log the trigger
  • manual if opened through the context menu
  • auto if opened through the scheduler job
• to be discussed when an experience sampling pop-up is skipped due to the active work hours (Fix Study Description Field in Onboarding Screen on Windows #322), should these be logged too?