Rename Helm chart to api7ee-demo-k8s

- Changed chart name from api7ee to api7ee-demo-k8s in Chart.yaml
- Renamed helm/api7ee directory to helm/api7ee-demo-k8s
- Updated all references in build.yml workflow
- Updated all references in helm-release.yml workflow
- Updated main README.md with new chart name
- Updated Helm chart README with new chart name
- Verified all old references have been replaced
- Chart packages correctly as api7ee-demo-k8s-{version}.tgz

helm/api7ee-demo-k8s/.helmignore

@@ -0,0 +1,23 @@
+# Patterns to ignore when building packages.
+# This supports shell glob matching, relative path matching, and
+# negation (prefixed with !). Only one pattern per line.
+.DS_Store
+# Common VCS dirs
+.git/
+.gitignore
+.bzr/
+.bzrignore
+.hg/
+.hgignore
+.svn/
+# Common backup files
+*.swp
+*.bak
+*.tmp
+*.orig
+*~
+# Various IDEs
+.project
+.idea/
+*.tmproj
+.vscode/