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`

.bash_aliases

@@ -1,3 +1,6 @@
+# Alias to restart plasmashell for Kubuntu Plasma session
+alias kapp-plasmashell='sudo pkill plasmashell && plasmashell --replace &> /dev/null &'
+
 # Aliases to use the correct python version
 alias python3='python3.9'
 alias pip3='python3.9 -m pip'