Create a way to scan all configured file paths
We often want to do checks on all configured file paths:
* relative paths
* runtime immutability
* sandbox immutability
We need to scan:
* type FILENAME
* HiddenServiceDir
* Log files
* *Port unix sockets
* ControlSocket
* Any options that activate a file path, but don't allow it to be configured (OnionAuth etc.)
Follow up to legacy/trac#32339 and legacy/trac#32344.
issue