[shell-common] Add XDG exports

shell-common/.config/shell-common/exports.sh

@@ -1,5 +1,14 @@
 # User specific environment
-PATH="$HOME/.local/bin:$HOME/bin:$PATH"
+
+# XDG Base Directories
+export XDG_BIN_HOME="$HOME/.local/bin"
+export XDG_CACHE_HOME="$HOME/.cache"
+export XDG_CONFIG_HOME="$HOME/.config"
+export XDG_DATA_HOME="$HOME/.local/share"
+export XDG_RUNTIME_DIR="${TMPDIR}/runtime-${UID}"
+export XDG_STATE_HOME="$HOME/.local/state"
+
+PATH="$XDG_BIN_HOME:$HOME/bin:$PATH"
 export PATH
 
 # User specific environment and startup programs