Ignore auto-generated file in catalog-be

Create a gitignore file to catalog-be and add autogenerated
file "Artifact-Generator.properties" to the ignore list.

Change-Id: Ia482e057c56d059c9ee5dde16fd6b0419623936e
Issue-ID: SDC-2724
Signed-off-by: andre.schmid <andre.schmid@est.tech>
diff --git a/catalog-be/.gitignore b/catalog-be/.gitignore
new file mode 100644
index 0000000..55771d9
--- /dev/null
+++ b/catalog-be/.gitignore
@@ -0,0 +1 @@
+/sdc-backend/chef-repo/cookbooks/sdc-catalog-be/files/default/Artifact-Generator.properties