Extensibility Walkthrough in capire (#405)

* Extension project template

* SalesRegion ->  x_SalesRegion

* enhanced order repo

* updated package-lock.json

orders-ext/.gitignore

@@ -0,0 +1,31 @@
+# CAP ext
+_out
+*.db
+*.sqlite
+connection.properties
+default-*.json
+.cdsrc-private.json
+gen/
+node_modules/
+target/
+
+# Web IDE, App Studio
+.che/
+.gen/
+
+# MTA
+*_mta_build_tmp
+*.mtar
+mta_archives/
+
+# Other
+.DS_Store
+*.orig
+*.log
+
+*.iml
+*.flattened-pom.xml
+
+# IDEs
+# .vscode
+# .idea