Add an URL field to Enviroments

What does this MR do?

Adds a field to the enviroments table to expose later in other features. Now I see the task list below, I noticed I forgot some minor things, but Ill adress those after the first review.

Are there points in the code the reviewer needs to double check?

The field is a string on the database, thus limited to 255 chars, which seems more than enough.

What are the relevant issue numbers?

Closes #19527 (closed)

Screenshots (if relevant)

Does this MR meet the acceptance criteria?

• CHANGELOG entry added
• API support added
• Tests
  • Added for this feature/bug
  • All builds are passing
• Conform by the style guides
• Squashed related commits together