[dev] Now wwsympa.conf is optional.  When it exists, its content overrides sympa.conf settings (along with possible defaults, even if the file is empty).
This is a part of work to migrate wwsympa.conf into sympa.conf.

- All "$wwsconf->{'paramname'}" in sources has been replaced with "$Conf::Conf{'paramname'}".
- On all executables, location of sympa.conf may be specified by command line "--config" option, SYMPA_CONFIG environment variable or compile-time default (in this priority).  wwsympa.conf may be specified by SYMPA_WWSCONFIG env. var. or default.
-- *Exception*: sympa_wizard.pl always uses compile-time defaults.
- Move wwslib::load_config() to Conf::_load_wwsconf() so that dependencies to wwslib are reduced.


git-svn-id: https://subversion.renater.fr/sympa/branches/sympa-6.2-branch@10236 05aa8bb8-cd2b-0410-b1d7-8918dfa770ce