Add templates to build TryMCP image

Author: Pavel Cizinsky, pcizinsky@mirantis.com
Change-Id: I35a667c667a1b68f178e5a7b4201400827a17235
diff --git a/trymcp-day01-image/template.json.env b/trymcp-day01-image/template.json.env
new file mode 100644
index 0000000..fb05cc3
--- /dev/null
+++ b/trymcp-day01-image/template.json.env
@@ -0,0 +1 @@
+PACKER_IMAGES_CACHE="${HOME}/packer_images_cache/"