feat(coderd): insert provisioner daemons (#11207)

* Adds UpdateProvisionerDaemonLastSeenAt
* Adds heartbeat to provisioner daemons
* Inserts provisioner daemons to database upon start
* Ensures TagOwner is an empty string and not nil
* Adds COALESCE() in idx_provisioner_daemons_name_owner_key

coderd/rbac/roles.go

@@ -155,6 +155,8 @@ func ReloadBuiltinRoles(opts *RoleOptions) {
 				// Users cannot do create/update/delete on themselves, but they
 				// can read their own details.
 				ResourceUser.Type: {ActionRead},
+				// Users can create provisioner daemons scoped to themselves.
+				ResourceProvisionerDaemon.Type: {ActionCreate, ActionRead, ActionUpdate},
 			})...,
 		),
 	}.withCachedRegoValue()