Implement the specified notification system for test suite failures on Jenkins

Originally created by @intrigeri on #10382 (Redmine)

This is what follow from tails/tails#10296 once we deem it’s time to go ahead.

Blueprint: https://tails.boum.org/blueprint/automated_builds_and_tests/automated_tests_specs/

Parent Task: tails/sysadmin#5288

Related issues

• Blocked by tails/tails#10296