* autogenerate JWT_SECRETS
Based on https://docs.gitea.io/en-us/command-line/#generate we will now autogenerate JWT_SECRETS if they are not defined.
In my opinion a much better idea than writing a value in the default config.
The check if the variables for the secrets are now 43 characters long i took out. Gitea generates itself suitable secrets, if the user given ones do not fit.
* drop ansible.builtin. syntax
