Fix Liberty group IDs

[infinitymdm]

Resolves #110

Summary

• Remove all uses of hash() for liberty group lookup, resulting in groups that work with Python's cross-session hash randomization.
• Improve identity and equality behavior for more consistent comparisons and merges on all liberty classes.
• Enhanced subgroup lookup supporting attribute-based filtering when (name, identifier) are insufficient.
• Add automatic rekeying for subgroup dictionaries to keep lookup fast.
• Allow Attribute to check equality against (name, value) 2-tuples.