Add scalability test support

Add new variables used in testnode software.
Add new rules to httpd, in order to make depositories accessible
by obfuscation.
ERP5Testnode: check that we develop erp5.util.

Otherwise, you'll have to run slapgrid manually.
Revert "ERP5Testnode: check that we develop erp5.util."

This reverts commit 64e08db209fdb9043f978977cecef86b5095a93f.