This makes standard use of shellcheck work without needing to provide extra configuration anywhere.
Also remove use of inline 'shellcheck disable' calls that are already defined in the .shellcheckrc and don't need to be set inline.
While I do not agree with _every_ style change, this will force Dokku to have consistent formatting across all shell scripts, which is arguably a Good Thing™.
The command used to reprocess everything is:
```shell
shfmt -l -bn -ci -i 2 -w .
```
This allows us to force another plugin as the default vhost implementation, or disable it altogether in favor of some higher-level proxy implementation, such as one that integrates with service discovery.
- remove deployed applications during dpkg purge
- disable all core plugins during dpkg purge
- ensure init files are removed
- ensure motd is removed
- remove all core plugins, dokku config files (including tls/sshcommand entries etc.) during purge
- remove all empty directories and broken symlinks in the DOKKU_ROOT and DOKKU_LIB_ROOT directories during purge
Note that we do not delete the dokku user itself as there might be other data we don't know about in this directory.
