Convert participation app to django model

Convert the participation app fields to a django model:
[participant_app_table.txt](https://github.com/DallasPetsAlive/new_digs/files/11402627/participant_app_table.txt)

Only field names and types needed. Id and color can be ignored.

**Do not add fields to this table that will exist on the Pets table or Persons table.** The pets table schema can be found on #2. We will create a link to the pet and person table when an app is submitted. Person table will just be very basic contact info: name, address, phone, etc.