Add the ability to manually CRUD an instructor/s

[theosiemensrhodes]

When talking with stakeholders they mentioned that the instructors might not want to create their own accounts. We need a way via the api for admins to create instructor accounts.

• This should be in the instructor service, with the input data of
  • name, firstname, email
• The service needs to handle creation, updating, and deleting of instructors
• You should just work with the users table for this issue, no need to work with better auth.