Resolve "Edit button on the staff page not functional"

What does this MR do?

This MR "fixes" the edit staff button, as this was not implemented yet. This MR contains the logic required to edit and delete staff. As well as some basic tests for these functionalities.

Screenshots

after

Does this MR meet the acceptance criteria?

• I have added tests to validate the new functionality.
• I have updated the documentation accordingly.
• I have added translations for all new client-side text.

Closes #128 (closed), #132 (closed)