Feature/serialization exe (#442)

* Initial changes to have serialization generate its own .exe

* Removed additional project from sln file

* remove all references to removed temporary project

* Moved shared contracts into own dll and fixed imports. Addressed PR comments

* Undid having a separate contracts project since that'll be a task for later on. Moved dbcellvalue and saveresultsrequest to Hosting, where they will be imported and shared by the service layer and serialization projects

* Switched backslashes in project reference in csproj file to forward slashes for consistency

* Moved necessary contracts back to service layer. Refactored CommandOptions to reduce code duplication. Addressed miscellaneous PR suggestions

* Accidentally left these files out of previous commit

* Initialized loggers for serialization and credentials with the logging directory provided by the cmd line arg, if there is one

* Changed default log directory paths for serialization and credentials. Removed unnecessary cast and added a copyright

* Changed name of generated executable for serialization service

* removed unnecessary object cast

* removing unnecessary imports and addressing other PR comments

build.json

@@ -17,6 +17,7 @@
   ],
   "MainProjects": [     
     "Microsoft.SqlTools.ServiceLayer",
-    "Microsoft.SqlTools.Credentials"
+    "Microsoft.SqlTools.Credentials",
+    "Microsoft.Sqltools.Serialization"
   ]
 }