GumGum: adds irisid and pubId for server side params (#2649)
GumGum: adds irisid and pubId for server side params (#2649)

* specifies us privacy is supported

* adds video support to gumgum md

* adds support for tcf 2

* adds new bid param to gumgum.md

* updates gumgum doc

* notes required mediaType for video products

* updates gumgum doc

* adds pubId and irisid params

* removes extra cell
prebid/prebid.github.io,prebid/prebid.github.io,prebid/prebid.github.io