Access permissions 1: Refactor access to roles

[lukasbestle]

Description

Summary of changes

$app->role() method is mainly a shortcut to $app->user()?->role() for us, but can also be used to directly access a specific role object.

Reasoning

Following PRs would add significantly more uses of $app->user()?->role() that can be shortened and DRYed by this.

Changelog

Features

• New $app->role() method that works like $app->user() to return a specific role or the role of the current user.

Housekeeping

• Move $app->roles() method to the AppUsers trait to increase the overview

Breaking changes

None

Docs

None (automatically documented via reference)

Ready?

• In-code documentation (wherever needed)
• Unit tests for fixed bug/feature
• Tests and CI checks all pass

For review team

• Add lab and/or sandbox examples (wherever helpful)
• Add changes & docs to release notes draft in Notion

[bastianallgeier]

Good cleanup. Do we worry about the coverage? I would merge it otherwise.

[lukasbestle]

The entire view action for the language view is not covered at the moment, this includes the only uncovered line in this changeset. I think at this point it's more important to continue with the permission additions than coverage.