SqlCmd Connect/On Error/Include commands support (#898)

* Initial Investigation

* Working code with include, connect, on error and tests

* Adding some loc strings

* Some cleanup and more tests

* Some dummy change to trigger build

* Adding PR comments

* Addressing PR comments

src/Microsoft.SqlTools.ManagedBatchParser/Localization/sr.resx

@@ -233,4 +233,16 @@
     <value>Variable {0} is not defined.</value>
     <comment></comment>
   </data>
+  <data name="SqlCmd_PathInvalid" xml:space="preserve">
+    <value>Path contains invalid characters.</value>
+    <comment></comment>
+  </data>
+  <data name="SqlCmd_PathLong" xml:space="preserve">
+    <value>Path too long.</value>
+    <comment></comment>
+  </data>
+  <data name="SqlCmd_FailedInclude" xml:space="preserve">
+    <value>Could not find included file {0}.</value>
+    <comment></comment>
+  </data>
 </root>