Move list of available "browsers" to xuris.ini

Needs saturnin 0.21+

dotfiles/saturnin/xuris.ini

@@ -0,0 +1,10 @@
+[xuris]
+
+    browsers = firefox
+    browsers = chromium
+    browsers = opera-beta
+    browsers = iceweasel
+    browsers = uzbl-browser
+    browsers = vimb
+    browsers = acclive
+    browsers = awget