Add the creating chatroom API.
Add the destroying chat room API.
Add the utility, providing methods to validate id(which should not have space, tab and newline characters).
Add the querying chat room APIs.
Fix the wrong validation on ID.
Add the id check on chatroom and group related APIs.
Add the const definitions(mainly for some return code and messages).
Move the result definitions to const/result.js
Return the error object instead of a string in chat room related APIs.
Return the error object in group related APIs.