Improve configuration comparison and event handling

[MusicDin]

Change to configuration comparator:

• Prevent comparison of unexported fields
• Remove event related code
• Fix comparison of nested maps
• Add option to show change prefixes (~, -, +)
• Expose comparison tree functions
• Improve tests

Changes to events:

• Introduce rules (events are now created based on detected changes and provided rules)
• Introduce rule path that allows anchoring changes (change is extracted from the anchored path segment instead from the path where actual change has happened)
• Improve tests