user sync utilities

[dgirardi]

Reimplementation of load-cookie and load-cookie-with-consent, from a single codebase, and adding GPP support.

GPP support is limited to accepting and relaying the gpp_sid and gpp query string parameters; there's currently no way to poll AMP for GPP.

Closes prebid/prebid-universal-creative#212
Closes prebid/prebid-universal-creative#226

Related: #2

[spotxslagle]

LGTM

[spotxslagle]

I approved on the assumption that everything is working as intended, but I am a bit curious why the resolveConsent var is used as a third parameter. As far as I can tell, resolveParams is only used by load syncs, which doesn't allow third argument to be passed in. I assume this is a placeholder for future development or something similar, but it did seem worth commenting on.

[dgirardi]

You're right it's unnecessary. I think at some point this function was more complex and I needed to mock this out from unit tests.

[bretg]

Let me see if I can summarize what this all about:

1. You guys don't like load-cookie in the PUC repo
2. So it's being banished to this separate repo
3. Which means that companies supporting AMP need to be alerted to this move and upgrade their procedures to pull from 2 repos where they formerly dealt with one.

The README is pretty good. We'll just need to upgrade the AMP docs. People are likely to miss this shift because there's no such thing as a "major release" in this area.