Finish the remaining work on the spec issues.

Scope

• Update JS parser to support new traits behavior #810
• Update JS parser to support new multi-format schemas #811
• Implement new simplified channel parameters JSON Schema required changes spec-json-schemas#413
• Implement new simplified channel parameters #815
• Possible inconsistence between isEmpty and pop in Channels class (V2)? #792

More info:

• Application of message traits (intentionally) replacing existing attributes spec#505
• Proposal to allow defining schema format other than default one (AsyncAPI Schema) spec#622