sf_soft: Add no 'noexec' tests around install/uninstall actions
Replace rpm-specific RPM_BUILD_ROOT by a more generic INSTALL_ROOT variable transmitted by the Makefile
Define source=. in rpm build, avoiding to copy tgz archive first
Change doc file names to match those used in wiki
Make sf_tmp_cleanup and sf_error_cleanup internal (non documented) as they are always called via sf_cleanup
Regenerate doc