[LibOS] test/apps: Move benchmark-http.sh to common_tools
This commit concerns web-server examples: Apache, Nginx, and Lighttpd.
Previously, benchmark-http.sh bash script was located under lighttpd
directory, and Apache and Nginx had symbolic links to it. This is
unintuitive. This commit moves benchmark-http.sh to a newly created
common_tools directory, and all web-server examples have symbolic links
to this new dir.
Dmitrii Kuvaiskii