Add option to disable access to api dashboard

Hi, this MR adds the following:

• an nginx rule to return a 403 on /api/admin
  • default is false to keep behavior
• a question to the install.sh script
  • it's only asked in the customization dialog
  • default is false

added AreaBackend AreaDeployment TypeEnhancement labels

Great contribution, thank you!

merged

mentioned in commit 610817a3

Glad it's considered useful :)