[request] Ensure base_url() always has a trailing '/' (closes #3955093) Just as an example, cubicweb.ajax.js is clearly written under the assumption that BASE_URL/baseuri() - which simply contains req.base_url() - has a trailing /.

option_group_changed('port', 'main', 'web')
option_group_changed('query-log-file', 'main', 'web')
option_group_changed('profile', 'main', 'web')
option_group_changed('max-post-length', 'main', 'web')