Moving verification of input to the earliest place is the best way to decrease the need to validate this further downstream.
Additionally, some of the existing checks were.... lacking :)
0.22.0 changed allowed values for app names, making it more difficult for users to fix their app names - you need to either downgrade+rename or recreate the app. The `apps:rename` command can now rename these old applications to the new standard.
Also drop some app name verification from internal commands. Duplicate verification doesn't help much, and though it isn't excessively slow, it does prevent us from running commands against old apps that exist.
Refs #4267
The `tls` name is no longer a reserved app name, and can be used by applications. This was previously a reserved app name due to it's use as a place for global SSL certificate files; Dokku has not supported global SSL certificates for many releases, and thus there is no need to reserve the name.
