Add the ability to exclude keyboards from travis builds (#11178)

* add the ability to exclude keyboards from travis builds

* add filtering to make all:

* only skip keyboards during make all:

* working implementation

* forego a CI_KEYBOARDS variable

* optimize the startup by only listing keyboards once

* add sort -u to all list_keyboard invocations

* move the if else if tree back to 1 level

util/list_keyboards.sh

@@ -0,0 +1,10 @@
+#!/bin/sh
+# Temporary shell script to find keyboards
+#
+# This allows us to exclude keyboards by including a .noci file.
+
+find keyboards -type f -name rules.mk | grep -v keymaps | while read keyboard; do
+	keyboard=$(echo $keyboard | sed 's!keyboards/\(.*\)/rules.mk!\1!') 
+
+	[ "$1" = "noci" -a -e "keyboards/${keyboard}/.noci" ] || echo "$keyboard"
+done