Improvements and Package Updates

[phantomcosmonaut]

• liquid file unregisterCallbacks method no longer takes functional argument
• liquid file added typed parameter for callback method
• Generator now uses params instead of dictionary for registering hubs
• Generator support for Serverless Hubs
• [Breaking] Generator now relies on SigSpecRegisterAttrbiute to register methods for hub operations invokable by the client. Alternative was to introduce a SigSpecIgnore, but this was cleaner and easier. Necessary to help support serverless hubs and reduces code complexity
• Package updates

[RicoSuter]

Are you still interested in this PR? Can you maybe fix the conflicts?