MEDIUM: ocsp: Create new do-ocsp-request action

MEDIUM: ocsp: Create new do-ocsp-request action

Create a new 'do-ocsp-request' http-request and "tcp-request content"
action. When an SSL handshake occurred and was successful, the action
checks for a client certificate. If any is provided and it contains an
OCSP URI, we build an OCSP request and send it to the responder. No
other action is performed until a response is processed or a timeout
occurs.
When the response is received, we check its signature thanks to an
issuer certificate that should be in the issuer tree (see
'issers-chain-path' option), check its expiration dates and the client
certificate's status, and put the status and error reason (if any) in
the user provided "status-var" and "reason-var".
By default the action denies the request is the received status is not
'good' but this can be tuned thanks to the 'no-deny' option.