Add wearable versioning

[meelrossi]

We need to find a mechanism to version wearables to prepare for future changes due to avatars 2.0 initiative

Possible future changes

V1: Includes hides, replaces, names and description, no Version parameter.
V2: removes replaces, adds version, add new category Hands
V3: remove hiding system, defines spring bones metadata
V4: removes accesories categorization and add subcategorization
V5: adds custom metadata structure and values from content creator
V6: add flags like "adult only", "game ready" or "violent content"

This change requires changes in explorer, catalyst and dapps