Resolve "creator/participant differentiation (login)"

Closes #76 (closed)

Proposed changes

• Users are not differentiated whether they log in as creator or participant

Testing instructions

• Before login, try to reach /participant
• Before login, try to reach /creator
• Log in with any data as a creator
  • Try to access /participant
• Log in with any data as a participant
  • Try to access /creator

Please think outside the box when testing!

Expected result

• When not logged in, you will be redirected to /home. A message appears that you are not allowed to visit the requested page.
• When logged in as creator, you will get redirected to /creator
• When logged in as creator, you are not allowed to visit /participant
• When logged in as participant, you will get redirected to /participant
• When logged in as participant, you are not allowed to visit /creator