Extend the mount manager to support more transformers than format. The
transformers allow altering the mount before it is passed to the mount
handlers. These could be one-time actions which are needed to perform
the mount.
Adds mkdir and mkfs actions which can be used to prepare the arguments
for a mount. The actions can be limited to actions within the target
mount directory or plugin directories.
Signed-off-by: Derek McGowan <derek@mcg.dev>
be9f183f45