postgres: announce a consumer failed for minutes, and its recovery

A provider failed every consumer for a day and said so only in its journal
(hq issue 179). The provisioner loop now emits provisioner.failing after five
minutes without a success — create, check or secret — and repeats it every
fifteen; provisioner.recovered on the next success, on withdrawal, and on the
first success after a restart, so the controller can name it in status
(hq ADR 0224).

modules/postgres/cmd/postgres-provider/harness_test.go

@@ -11,10 +11,11 @@ import (
 )
 
 type recorder struct {
-	created []Provision
-	removed []string
-	held    bool
-	failing error
+	created  []Provision
+	removed  []string
+	held     bool
+	failing  error
+	holdsErr error
 }
 
 func (r *recorder) Create(_ context.Context, p Provision) error {
@@ -30,7 +31,12 @@ func (r *recorder) Remove(_ context.Context, as string, _ map[string]any) error
 	return nil
 }
 
-func (r *recorder) Holds(context.Context, Provision) (bool, error) { return r.held, nil }
+func (r *recorder) Holds(context.Context, Provision) (bool, error) {
+	if r.holdsErr != nil {
+		return false, r.holdsErr
+	}
+	return r.held, nil
+}
 
 type world struct {
 	t        *testing.T