Add Json WebServices discovery document

• Type: Story
• Status: Closed
• Priority: Minor
• Resolution: Completed
• Affects Version/s: 6.2.0 CE M4
• Fix Version/s: 6.2.0 CE M4
• Component/s: Portal Services, Portal Services > Legacy
• Labels: None
• Epic/Theme:
  • Platform
• Story Points: 3
• Git Pull Request: https://github.com/brianchandotcom/liferay-portal/pull/9050

Similar to the concept of WSDL, lets add json-based document for describing all api services.

this can be invoked like:

/api/jsonws?list

or to narrow down the list to certain service(s):

/api/jsonws?list=/dlapp/*,/user/*

This would also help to automatically build the clients.