Add datavirtualization extension (#21594)

* initial

* cleanup

* Add typings ref

* fix compile

* remove unused

* add missing

* another unused

* Use newer vscodetestcover

* newer dataprotocol

* format

* cleanup ignores

* fix out path

* fix entry point

* more cleanup

* Move into src folder

* Handle service client log messages

* remove unused

extensions/datavirtualization/.gitignore

@@ -0,0 +1,20 @@
+
+out
+node_modules
+*.vsix
+.DS_Store
+.idea
+.rpt2_cache
+test-reports/**
+
+# Jupyter paths
+wheels/**
+
+# service paths
+scaleoutdataservice/**
+
+# python paths
+python/**/**
+
+# coverage folder
+coverage/**