Add is teacher in any active edition endpoint

Labradoor Counter-MR: labradoor!73 (merged)

What does this MR do (summary)?

Adds a new endpoint which returns true/false depending on if a person has the teacher role in any active edition.

What changes have you made (detailed)?

• In AuthorizationController => Add Endpoint
• In AuthroizationControllerTest => Add Test

Does this MR meet the acceptance criteria?

• The main application was run to make sure the server still runs without errors.
• Tests were written to verify the behaviour of this code.
• Javadoc and other comments were added to make the code understandable.
• The code adheres to the style guidelines.