fst: improve config

The config struct more or less "grew" to what it is today. This change moves things around to make more sense and fixes nonsensical comments describing obsolete behaviour.

Signed-off-by: Ophestra <cat@gensokyo.uk>

test/test.py

@@ -69,8 +69,8 @@ def check_state(name, enablements):
     if len(config['args']) != 1 or config['args'][0] != command:
         raise Exception(f"unexpected args {config['args']}")
 
-    if config['confinement']['enablements'] != enablements:
-        raise Exception(f"unexpected enablements {instance['config']['confinement']['enablements']}")
+    if config['enablements'] != enablements:
+        raise Exception(f"unexpected enablements {instance['config']['enablements']}")
 
 
 def fortify(command):