[RFC PATCH] kbuild: move tags support to a shell script

[Sam Ravnborg]

As no-one else wanted to do so - I now moved the tags support
to a shell script of its own.
The usage is the same: make {tags,TAGS,cscope}

The ALLSOURCE_ARCHS suppport was lost in the transition - is it actually used by anyone?

I have given the patch only some light testing.

Could those of you that actually sues tags/cscope plese give it a try.

My naive transformation to a shell script could benefit from
a pair of critical eyes too.

I will await feedback on the script and ALLSOURCE_ARCHS
before I push it out.

	Sam