confirmation email backend

[elYanuki]

• api "sendconfirmation" route as a sub item of the rent "getbyid"
• should send a confirmation email to the student that contains a short text an a link to a page in the frontend
• the confirmation_status should be set to waiting
  • if the confirmation_status is already waiting nothing should change and a cc-error 1201 should be returned (see api docs)
• create tests for this

[elYanuki]

renamed the setVerificationMessage method to setVerificationStatus since thats what it does.. also changed the if to check if the status is already set instead of if its waiting.. since then it would just get stuck on waiting!?

Refactoring:

• renamed itUser to username
• moved logic from Resource into function sendConfirmation in Repository
• renamed getMailmessage to generateMailmessage since its not returning an existing param but creating the result from scratch
• moved logic for generating verification codes to the Rent class since the logic is contained to that class and this removes the need for a setter for the code. New method is named generateVerification_code and returns the code as well
• changed the setting of the status to not use the confirm function

[elYanuki]

coresponding code is reached and all params look fine but email is never sent

[elYanuki]

email is sent again, link is not working tho

[elYanuki]

email gets sent and link is working