Encryption: Refine secrets-related commands (#45201)

* CLI: Adjust 're-encrypt-data-keys' command

* CLI: Adjust 're-encrypt' command

* Multiple improvements on re-encrypt secrets migration

* Another bunch of code improvements

* Lint fixes

pkg/cmd/grafana-cli/commands/secretsmigrations/secretsmigrations.go

@@ -0,0 +1,28 @@
+package secretsmigrations
+
+import (
+	"time"
+
+	"github.com/grafana/grafana/pkg/infra/log"
+)
+
+type simpleSecret struct {
+	tableName  string
+	columnName string
+}
+
+type b64Secret struct {
+	simpleSecret
+}
+
+type jsonSecret struct {
+	tableName string
+}
+
+type alertingSecret struct{}
+
+func nowInUTC() string {
+	return time.Now().UTC().Format("2006-01-02 15:04:05")
+}
+
+var logger = log.New("secrets.migrations")