Allow other users access to the panel

[eXpl0it3r]

The SFML Projects should be a community driven project for that more than just me need access to the panel while not granting everyone admin rights.

• [x] Add editor role
• [x] Grant only necessary permissions
• [x] Check the permission set
• [ ] Create Editor page with information
• [x] ~Check if there's a reCAPTCHA plugin for the panel login~
• [ ] Create a sign-up form for those interested in helping
  • [ ] Add uniform
  • [ ] Add uniform-recaptcha

[eXpl0it3r]

The first three steps have been implement with the migration from Kirby 2 to Kirby 3: https://github.com/eXpl0it3r/sfmlprojects/commit/be74bc822cad576085fc369ff63f30da8825b7bd

The second to last step is not needed.