Create notification system for use with blocks

[donnapep]

Is your feature request related to a problem? Please describe

There are some blocks that need to display notices specific to the functionality they provide. If these notices are displayed as part of the block, then they will be shown at the location where the block exists on the page. This is not ideal as it means notices could be displayed at odd locations, and would be easier for the user to miss.

Describe the solution you'd like

Create a facility that enables blocks to display system-level notices near the top of the Sensei page. It should be possible to hook into this notification system from other plugins, so that they can also display their own notices.

Describe alternatives you've considered

Displaying notices as part of the block, which suffers from the aforementioned problems.

[matticbot]

➤ donnapep commented:

This card can be repurposed once https://trello.com/c/1o1oQKY4/751-research-approach-for-notification-system is done.