Adding custom message in banner

Review Request #8824 — Created March 18, 2017 and submitted — Latest diff uploaded

Information

khp
Review Board
master

Reviewers

Read-only mode is a feature that can be enabled by the admin to disable
most backend changes by regular users. This commit adds a custom
message for the banner when in read-only mode. The message can be
optionally added through the admin panel right under where the admin
would enable/disable read-only mode.

Ran js-tests - passed
Ran python tests - most passed, some failures fixed in future commit
Checked changing value in admin panel reflects in banner