Improve i3 configurations to work alongside Plasma

+ Add alias to restart plasmashell
+ Fix date display in conky for i3 sessions
+ Fix polybar height for better display with new font size
+ Add floating rules in i3 for Steam and Signal
+ Use i3 configuration to bind custom keys instead of xbindkeys
+ Relocate `.desktop` files to `.local/share/applications`
+ Symlink desktop files for startup applications to `.config/autostart`

.local/share/applications/mullvad-vpn.desktop

@@ -0,0 +1,21 @@
+[Desktop Entry]
+Categories=Network;
+Comment[en_US]=Mullvad VPN client
+Comment=Mullvad VPN client
+Exec="/opt/Mullvad VPN/mullvad-vpn" %U
+GenericName[en_US]=
+GenericName=
+Icon=mullvad-vpn
+MimeType=
+Name[en_US]=Mullvad VPN
+Name=Mullvad VPN
+Path=
+StartupNotify=true
+StartupWMClass=Mullvad VPN
+Terminal=false
+TerminalOptions=
+Type=Application
+X-DBUS-ServiceName=
+X-DBUS-StartupType=
+X-KDE-SubstituteUID=false
+X-KDE-Username=