Log improvements (#163532)

* - expose log level in the proposed api
- ability to set log level per logger

* fix tests

extensions/vscode-api-tests/package.json

@@ -33,7 +33,7 @@
     "taskPresentationGroup",
     "terminalDataWriteEvent",
     "terminalDimensions",
-	"tunnels",
+    "tunnels",
     "envShellEvent",
     "testCoverage",
     "testObserver",
@@ -44,6 +44,7 @@
     "treeViewReveal",
     "workspaceTrust",
     "telemetry",
+    "extensionLog",
     "localization"
   ],
   "private": true,