Use IPIP-412 parameters to request ordered CARs with duplicates rather than defaults

[aschmahmann]

IPIP-412 introduces the order and dups parameters for CAR retrievals using the HTTP Gateway API. Currently bifrost-gateway does not use these parameters and changes like #160 assume that order=dfs; dups=y is what's used by default.

We should switch to order=dfs; dups=y so that we are not tied to the default behavior of backing-gateways like Saturn.

This is an easy enough switch to do, but will cause cache in Saturn so flagging folks to make sure we're ready to do this.

cc @aarshkshah1992 @DiegoRBaquero @willscott @lidel

[hannahhoward]

From a lassie standpoint, this is fine. We already parse the dups param and act on it.