Update dev container config and guidance (#886)

* Initial dev container changes

* Update readme's

* Clean up dev container

* Cleanup

* Use in-memory db

* Indent

* Update devcontainerreadme.md

* Update appsettings.json

* Update appsettings.json

---------

Co-authored-by: bamurtaugh <brmurtau@microsoft.com>

src/Web/appsettings.json

@@ -17,4 +17,4 @@
     },
     "AllowedHosts": "*"
   }
-}
+}