gnome: clean up ringmainwindow.cpp

Define custom widgets in separate files and move
commonly used functions to utils:
- moved get_index_from_selection() to utils/models
- moved place_new_call() to utils/calling
- moved the contacts treeview to contactsview
- moved the history treeview to historyview

Refs #71530

Change-Id: Ia20e8d3bc3cfe997d38c880854205f063f0244a0
diff --git a/CMakeLists.txt b/CMakeLists.txt
index 83c3c97..f8da86b 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -195,6 +195,14 @@
    src/backends/edscontactbackend.cpp
    src/delegates/pixbufdelegate.h
    src/delegates/pixbufdelegate.cpp
+   src/contactsview.h
+   src/contactsview.cpp
+   src/historyview.h
+   src/historyview.cpp
+   src/utils/models.h
+   src/utils/models.cpp
+   src/utils/calling.h
+   src/utils/calling.cpp
 )
 
 # compile glib resource files to c code