staging: Clean up files installed into the sysroot

There are a variety of files being installed into $datadir which we
don't need. Pick the top "offenders" which amount of thousands of files
and simply don't install them. These include things like test data,
terminfo data, locale data for native tools and so on. This saves
copying these files into native and target sysroots and should improve
performance (smaller sstate, fewer files to copy around).

With this and the python recipe change, alsa-tools went from:

recipe-sysroot: 18357
recipe-sysroot-native: 14129

to

recipe-sysroot: 10809
recipe-sysroot-native: 8079

which is a decent improvement.

(From OE-Core rev: 366c72941fe1c24d0b1d96df46e13cb9eb4e79d6)

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta/classes/staging.bbclass

@@ -28,11 +28,15 @@ SYSROOT_DIRS_BLACKLIST = " \
     ${mandir} \
     ${docdir} \
     ${infodir} \
+    ${datadir}/X11/locale \
     ${datadir}/applications \
+    ${datadir}/bash-completion \
     ${datadir}/fonts \
     ${datadir}/gtk-doc/html \
+    ${datadir}/installed-tests \
     ${datadir}/locale \
     ${datadir}/pixmaps \
+    ${datadir}/terminfo \
     ${libdir}/${BPN}/ptest \
 "