Implemented version lists.

Further work on this is still needed. Currently there is no sorting or filtering of any kind. In addition,
changes need to be made to fix issues with bad ETags since the current system here is based on MultiMC 4's
version list system before it was fixed.

CMakeLists.txt

@@ -172,6 +172,7 @@ gui/aboutdialog.h
 gui/consolewindow.h
 gui/instancemodel.h
 gui/instancedelegate.h
+gui/versionselectdialog.h
 
 multimc_pragma.h
 
@@ -200,6 +201,7 @@ gui/aboutdialog.cpp
 gui/consolewindow.cpp
 gui/instancemodel.cpp
 gui/instancedelegate.cpp
+gui/versionselectdialog.cpp
 
 java/javautils.cpp
 java/annotations.cpp
@@ -217,6 +219,7 @@ gui/taskdialog.ui
 gui/browserdialog.ui
 gui/aboutdialog.ui
 gui/consolewindow.ui
+gui/versionselectdialog.ui
 )