Multi-tendency support

[ramank775]

As this project provides a generic solution for message communication, It can be used in multiple projects which are isolated to each other. However currently it is not possible to use the same deployment into multiple projects due to the way project is currently structured.

In order to support the multi-tendency there are changes required in the project structure which include but not limited to:

• Add support for namespace/ project to differentiate multiple projects and provide level of isolation.
• Change in message schema to be lighter and more generic in nature.
• Offload ability to login/signup directly from client to individual server. Use server to server communication between our server and project server for creating Authentication Token and User Profile if needed.
• Project level properties to enable disable specific features like weather to enable persistent message for delivered message, ability to create groups, etc.
• Offload responsibility to delivery offline message (functionality currently provided by notification MS) to individual project.
• Route message based on specific channel type explicitly specified by client application.
• Add webhook functionality for server to server communication between our server and project server.

Other than the changes which are required or necessary to support multi-tendency there are few changes which are not necessary but important to have.

• Use protobuffer to maintain message schema.
• Add support for custom channel type, to provide extensibility to support individual project use case.