Add support for mirroring requests while performing B/G deployments with
Gateway API. A `RequestMirror` filter pointing to the canary service is
added to the HTTPRoute during a Canary run. During the Canary run, drift
correction for `.spec.rules[].filters` is disabled to avoid removing the
mirror filter.
Signed-off-by: Sanskar Jaiswal <jaiswalsanskar078@gmail.com>