Custom targets (labels) for queries - Backend

[sharon-fdm]

[sgress454]

@dantecatalfamo just to record what we worked through today for posterity (feel free to put it in the ticket description under a "technical design" heading):

• New join table query_labels, with query ID and label ID.
• Update to ListScheduledQueriesForAgents code to accept a host ID param, and to query for query rows that either don't have an associated query_labels row, or have one whose label_id matches a label that the host_id is a member of.
• API updates as laid out in #16413 API design: Add labels to queries API  #26589. It's not mentioned explicitly in those docs but I'd be 👍 on the labels_include_any property in the "get query" having the same format that the software titles response does, e.g.:

[ { name: "some label", id: 123 } , { name: "some other label", id: 456 }, ... ]

• GitOps may end up as a subtask of Custom targets (labels) for queries - GitOps #26831.

[dantecatalfamo]

@sgress454 We should also leave a comment on the parent issue so product sees the changes and updates the API docs 🙂

[fleet-release]

Custom labels bloom,
Queries find their targets swift,
In cloud city's loom.