[SD-974] Adding channel level notification.
Merge remote-tracking branch 'upstream/master'
[SD-974] adding notifications for ingest channel.
[SD-974] fixing the flake errors.
[SD-974] fixing the behave errors.
[SD-974] refactoring to code to use user list.
[SD-974] fixing templates as per PR comments. Made it consistent to "Team".
[SD-974] modified the code as per PR-453 comments.
Merge remote-tracking branch 'upstream/master'
[SD-974] fixing the method name.
[SD-974] Fixed the behave AD test.
[SD-974] Refactored the code for checking email notification are allowed or not.
Merge pull request #453 from mdhaman/master

(feat)[ingest] -[SD-974] Implementing notification for ingest channel