Feature: Tasks (core) (#12184)

* initial

* string sanitize

* hygiene

* build task

* added build task

* hygiene

* initial tasks view

* finished tasks

* add sql carbon tags and undo changes

* remove task message

* fix tasks tests

* removed extension stuff

* add problem matcher

* remove extra space

* undo extension changes

* add problem matcher to mssql

extensions/mssql/package.json

@@ -20,6 +20,11 @@
     "postinstall": "node ./build/postinstall.js"
   },
   "contributes": {
+    "problemMatchers": [
+      {
+        "name": "tasks"
+      }
+    ],
     "commands": [
       {
         "command": "mssql.exportSqlAsNotebook",