Rebuild proxy classes if security policy changes
We need to monitor the settings (or probably later called "Policies.yaml") file and rebuild the AOP proxy classes if it changes.
[FEATURE] Track all configuration changes
This change set greatly improves the file monitoring of FLOW3's
system relevant files, such as class files, settings, object
configuration, policies and translations.
In Development context, changes to any of the above will be
tracked and the related caches are flushed. For performance
reasons, the new mechanism does not rely on the tagging
feature of the cache framework, but uses the new Simple
File Backend and rather flushes a few caches too many than
missing an important change.