Add visualisation of the account's third party IDs in the account editor.

A category won't be shown if there are no relevant IDs (will add the ability to add new ones later).

Part of network/neochat#565

![image](/uploads/7da00b0b4acf90d145c09969ac2a91e1/image.png)

src/CMakeLists.txt

@@ -175,6 +175,8 @@ add_library(neochat STATIC
     models/roomtreeitem.cpp
     models/roomtreeitem.h
     foreigntypes.h
+    models/threepidmodel.cpp
+    models/threepidmodel.h
 )
 
 set_source_files_properties(qml/OsmLocationPlugin.qml PROPERTIES