Change races to activities

[Mathieu414]

See the project item for the idea of the changes.

Quite a lot of things. Changed a bit how the data is displayed in the activities accordion, so that it becomes clearer what is the event description and what is your own registration.

[Atmos4]

@Mathieu414 you might want to rebase to master with this branch! You can also either worktree or stash our progress to make it easier to review, and create another work item!

[Atmos4]

I don't like the current data migration:

• it has var-dumps. Please if you want to display things, format them in a readable way
• it does not work and throws errors. Clean it up before the merge
• it is non revertible. Please implement a "revert" button, or better yet use the built in migrations from doctrine!

If you want to generate an empty migration file with Doctrine, you can use the following command:

php bin/doctrine migrations:generate

To be clear, the real blocker here is that it does not work. If it would work flawlessly I would probably approve. I however think this migration is dangerous, and would appreciate if you make the code cleaner and less risky to execute.

So since it just does not work, I would like if you would try to add a test for the migration! If you want some help creating a test I can of course help out :)