controller/v0.28.0

Changelog

• fdd75c9 config agent: reduce full config check frequency from 5s to 1m and compare hashes instead (#3028)
• 8781c98 controller: stop exporting metrics for pubkeys removed from the ledger (#3931)
• cc3a781 controlplane: retire doublezero-admin crate (#3906)
• 69dc808 serviceability: validate device mgmt_vrf field (#3881)