config: add mousepad configuration (dconf settings)

add a hook to update the systemd dconf database during build
https://help.gnome.org/admin/system-admin-guide/stable/dconf-custom-defaults.html.en
https://help.gnome.org/admin/system-admin-guide/stable/dconf-keyfiles.html.en
https://help.gnome.org/admin/system-admin-guide/stable/dconf-lockdown.html.en
https://help.gnome.org/admin/system-admin-guide/stable/dconf-profiles.html.en
Fixes #40

config/includes.chroot/etc/dconf/db/local.d/01-mousepad

@@ -0,0 +1,27 @@
+[org/xfce/mousepad/preferences/view]
+indent-width=-1
+show-line-marks=false
+highlight-current-line=false
+word-wrap=true
+show-right-margin=false
+color-scheme='vibrant'
+show-line-numbers=true
+insert-spaces=false
+match-braces=true
+indent-on-tab=true
+right-margin-position=80
+show-line-endings=false
+tab-width=4
+show-whitespace=false
+smart-home-end='disabled'
+auto-indent=true
+
+[org/xfce/mousepad/preferences/window]
+menubar-visible=true
+statusbar-visible=true
+toolbar-visible=true
+
+[org/xfce/mousepad/state/search]
+replace-all=true
+match-case=false
+replace-all-location=1

config/includes.chroot/etc/dconf/profile/user

@@ -0,0 +1,2 @@
+user-db:user
+system-db:local