Background: Event and incident tags were researched for https://issues.redhat.com/browse/OSDEV-1609. Unlike Event tags where they should be a fixed set of tags to choose to apply to events, incident tags should be able to be anything SREs and SRE managers deem appropriate for their analysis/analytics needs.

Acceptance Criteria: Permit applying custom tags to incidents. These tags should be visible and incidents should be able to be queried by tag.

Additional Information: Consider the API/DB implementations for creating, fetching tags to then search incidents via those tags. Its probably not unreasonable to expect multiple tags being applied to the same incident for different analytics or organizational reasons.