Add model & endpoints for user feedback

[scy]

Implements the feedback form parts of #37.

@t-muehlberger, the endpoints can be used to check whether a token is still valid to be used, and also to provide the Destination data required to display the MEP. I’ve also included a language field that you can use to initialize the frontend to; it will be set to the language in use when initiating the call. This is useful if the User opens the feedback form from a different browser (e.g. on their phone).

@t-muehlberger, would you like me to add a mockup version of this to #141? I’d prefer to avoid that, because it’s additional effort to copy-paste the code around and create a mockup for it, but if it makes your life significantly easier I’ll do it nevertheless ;)

@jbethune, if you want to, you can review this. Maybe … idk, react with 👀 on this description when you intend to do one, so that I don’t merge it before you’re done?

[t-muehlberger]

@scy I don't really need a mock version of the endpoint, I will checkout this brach. What is the best way how I can get a feedback-token for testing?

[scy]

What is the best way how I can get a feedback-token for testing?

Right now, probably by inserting a row into the database manually. For example:

sqlite3 dearmep.sqlite "insert into user_feedback (token, issued_at, expires_at, destination_id, calling_code, language) values ('FTHNZBGH', '2023-10-04 09:05', '2023-10-11 09:05', '96750', 49, 'de');"

Sorry, didn’t have time to write a CLI for that just now.

Make sure to run dearmep db init first to create the necessary table. I’m also working on a prepared base database dump for development with all the new tables that we have, but that too won’t include a token.

[t-muehlberger]

@scy perfect thank you, the SQL Insert will work just fine for me.
Yes I have already initiated my local version of the DB to be up to date with the latest schema changes.