Improve CONNECT reference adapter documentation

https://connectopensource.atlassian.net/wiki/spaces/CW/pages/782729217/Implementing+an+Adapter+for+CONNECT+Adoption

Note: The research work is done on this ticket. We need to polish up the documentation only.

Completion criteria:

• Add clearer and more detailed instructions on how to create a reference adapter for CONNECT

• Provide code examples where appropriate

• Clearly describe any security requirements

• If possible, describe how to create integrate a custom adapter that is not immediately referenced in standard mode (how to add an entry in internalExchangeinfo.xml, etc)

• Add guidelines for secured,unsecured and java impl interfaces.

QA:

Page is reviewed