Revert "connect `request-queued` signal conditionnally"

This reverts commit c441ec7aaf4fabc1a32a618bbab3b688d7804628.

As discuted with @fanglingsu, the problem isn't an overhead introduced
by `request-queued` signal. So the conditionnal connection isn"t need.
auto-response-header: generalisation of content-security-policy

auto-response-header supersede previous content-security-policy setting.

This setting is a list of "pattern name=value" entries. When a pattern
match a requested uri, the HTTP header "name: value" is added to
response.
auto-response-header: make value optional

an optional value result removing a previously setted header.