Added endpoint for fetching all notebook jobs (#834)

* Added endpoint for fetching all notebook jobs

* Refractored NotebookJobInfo to AgentNotebookInfo to make it more consistent with the rest of the codebase

* Added Notebook History endpoint in contracts.

* Added Create, Update, Delete notebook endpoints. Also added separate fetch template, materialized notebook endpoints. This will make the Notebook Request and Notebook History responses lighter.

* AgentNotebookInfo is now derived from AgentJobInfo

* added fetch noteook history endpoint

* Added fetching materialized notebook endpoint

* Added code for cleaning up the directory

* Added create notebook api

* Added Update and delete notebook job

* Fixed notebook history API

* Added last run info to the script and template folder

* Added execute database feature for notebook Jobs

* SQL commands are now using sqlparameters to prevent
any injection attacks

* Changed rundate and runtime to string to preserve
leading zeros

* integration test for agentnotebooks api

* Made some changes mentioned in PR

* Refactored the code, removed enpoint logic from the notebook handler and
wrote test cases

* changes select statements, fixed a bug in the test job cleanup
and fixed other stuff mentioned in the PR.

* added notebook_error column in notebook history select statement

* Added get template notebook endpoint

src/Microsoft.SqlTools.ServiceLayer/Utility/FileUtils.cs

@@ -9,6 +9,7 @@ namespace Microsoft.SqlTools.ServiceLayer.Utility
     internal static class FileUtilities
     {
         internal static string PeekDefinitionTempFolder = Path.GetTempPath() + "mssql_definition"; 
+        internal static string AgentNotebookTempFolder = Path.GetTempPath() + "mssql_notebooks";
         internal static bool PeekDefinitionTempFolderCreated = false;
 
         internal static string GetPeekDefinitionTempFolder()