zathura: Add simple zathura configuration

Sets zathura to open itself with the recolored version of the pdf
instead of the usual (mostly white background/black lettering).
This works in concert with styler which will automatically set the
correct coloring in 'zathurarc' for the currently applied desktop theme.

Changes the copy mode to send anything copied to the clipboard instead
of primary selection, since I never use primary selection.

Adds a simple keymap to print a file (p) and makes it slightly harder to
accidentally rotate a file by moving rotate from r to s-r.

zathura/.config/zathura/zathurarc

@@ -0,0 +1,8 @@
+
+
+set recolor                     "true"
+set selection-clipboard         "clipboard"
+
+map r reload
+map R rotate
+map p print