Allow to send notifications when Admins cancel jobs

[davelopez]

Stretch goal for #19487, thank you, @GarethPrice-Aus for proposing it.

Sending job canceled notifications

Admins can now decide to notify users when they cancel any of their jobs.

After selecting the jobs to cancel and providing a message, admins can enable the switch to send notifications. One notification will be sent per user (even if multiple jobs belonging to the same user were canceled).

The notification will be displayed to the user after a few seconds and potentially get an email if the user has the appropriate notification settings. If multiple jobs for the same user were canceled then all of them will be listed in the notification.

Clicking any of the jobs (tool IDs) listed in the notification will display a new page with the job details.

Small API change

Listing jobs with user_details will include the user_id in addition to the existing user_email for convenience.

How to test the changes?

• I've included appropriate automated tests.
• This is a refactoring of components with existing test coverage.
• Instructions for manual testing are as follows:
  1. [add testing steps and prerequisites here if you didn't write automated tests covering all your changes]

License

• I agree to license these and all my past contributions to the core galaxy codebase under the MIT license.