Revert "Added kernel dummy package: sample" (no need anymore)

NOTE: kernel/sample/Makefile.am is left as an example but not used anymore

This reverts commit 3074ad70db777694b401b1cd3980f74301b0339d.
Moved old (obsolete) code into '/kernel/old/'

+ cleanup
Moved htmlhelp.* to Singular/ from kernel/ (may be used in some future)
Cleanup scons leftovers
Moved /kernel/{Cache*.h,interpolation.{h,cc},minpoly.{h,cc}} (orig. from /Singular/) to kernel/linear_algebra/
Moved all the outdated  modgen related stuff to /old_modgen/ for now
Removed HAVE_CONFIG guards

fix: fixed the inclusion of configure-generated *config.h's
Updated the package diagramm for /kernel/