[config] Lowercase the FQDN we get from the OS (closes #5040345) Browsers convert the host name part of URLs to lowercase. This has the unfortunate effect of triggering various CORS error messages in CubicWeb (because the Origin: header will contain lowercase letters). As per RFC 4343, host name comparison should be case-insensitive. So let's put it in lowercase when we grab it from the host system. If admins put uppercase letters in "host" or "base-url" in their all-in-one.conf, then it's their fault.

\.svn
^build$
^dist$
\.pyc$
\.pyo$
\.bak$
\.old$
\~$
\#.*?\#$
\.swp$
^doc/book/en/apidoc$
\.old$
syntax: regexp
.*/data/database/.*\.sqlite
.*/data/database/.*\.config
.*/data/database/tmpdb.*
.*/data/ldapdb/.*
^doc/html/
^doc/doctrees/
^doc/book/en/devweb/js_api/
data/pgdb/