Add .desktop file and icon

data/sm.puri.Calls.desktop

@@ -0,0 +1,13 @@
+[Desktop Entry]
+Name=Calls
+GenericName=Phone
+Comment=Make telephone calls
+# Translators: These are desktop search terms. Do not translate semicolons, end line with a semicolon.
+Keywords=Telephone;Call;Phone;Dial;Dialer;PTSN;
+# Translators: Do NOT translate or transliterate this text (this is an icon file name)!
+Icon=sm.puri.Calls
+TryExec=calls
+Exec=calls
+Type=Application
+Terminal=false
+Categories=GNOME;GTK;Telephony;