Complete refactor of TOTP integration

* Eliminate TOTP logic from GUI elements
* Consolidate TOTP functionality under the Totp namespace
* Eliminate guessing about state and encoders
* Increased test cases
* Add entry view column for TOTP [#2132]
* General code cleanup, reduction of unnecessary steps, separation of concerns
* Rename SetupTotpDialog to TotpSetupDialog for consistency

src/gui/entry/EntryModel.h

@@ -42,7 +42,8 @@ public:
         Modified = 8,
         Accessed = 9,
         Paperclip = 10,
-        Attachments = 11
+        Attachments = 11,
+        Totp = 12
     };
 
     explicit EntryModel(QObject* parent = nullptr);