Encryption: De-duplicate encryption code with extensible service (#52472)

* Encryption: De-duplicate encryption code with extensible service

* Fix Wire injections

* Fix tests

* Register reload handler

pkg/services/encryption/encryption_test.go

@@ -0,0 +1,22 @@
+package encryption
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func Test_KeyToBytes(t *testing.T) {
+	t.Run("with regular secret", func(t *testing.T) {
+		key, err := KeyToBytes("secret", "salt")
+		require.NoError(t, err)
+		assert.Len(t, key, 32)
+	})
+
+	t.Run("with very long secret", func(t *testing.T) {
+		key, err := KeyToBytes("a very long secret key that is larger then 32bytes", "salt")
+		require.NoError(t, err)
+		assert.Len(t, key, 32)
+	})
+}