fix: prevent /etc/ merge issues (#43)

* fix: prevent /etc/ merge issues
discussed at length in #28
also including tons of comments about the issue

* fix: change references of /etc/ to /usr/etc

etc/skel.d/.config/autostart/ublue-firstboot.desktop

@@ -1,7 +1,7 @@
 [Desktop Entry]
 Name=uBlue First Boot Setup
 Comment=Sets up uBlue Desktop Correctly On FirstBoot
-Exec=/usr/bin/yafti /etc/yafti.yml
+Exec=/usr/bin/yafti /usr/etc/yafti.yml
 Icon=org.gnome.Terminal
 Type=Application
 Categories=Utility;System;