interlace: Fix negotiation issues

    interlace: Don't set field-order field for progressive caps

    That would cause negotiation issue

    interlace: Drop framerate from query caps of sinkpad

    Query caps should return caps which represent the element can accept,
    not resulting format.

    Fixing negotiation error with
    gst-launch-1.0 videotestsrc ! video/x-raw,framerate=25/1 ! interlace field-pattern=0 ! fakesink