WIP: add reporting feature

[janikga]

• fixes Add reporting feature for malicious posts #27

WIP due to the following issues

• reporting state is not persisted once the posting is selected and redirected to /offer-help/:postingId --> any suggestions?
• reporting functionality could not be tested due to the lack of permissions. As this is my first time using Firebase, please double-check this section and/or test that it works if you have the permissions :)

Video Recording

• https://imgur.com/a/jlblLeT

[janikga]

would be lovely if someone with more firebase knowledge than me could double-check this!

[kenodressel]

Here my ideas to simplify it:
Use documentRef.set this is the upsert function
To add a uid to the array we could use https://cloud.google.com/firestore/docs/manage-data/add-data#update_elements_in_an_array
Then this can all be done in one query.

[janikga]

@kenodressel updated. I see that the develop branch is set as the new default, should I rebase the PR against it?

[kenodressel]

@jagaSto yes please :)

[janikga]

I'll make a new PR since Entry.js does not exist anymore :D

[kenodressel]

I think this makes sense