Showheroes Bid Adapter : full rework of the adapter (prebid#12283)

* switch to openRTB endpoint

* refactor and add more tests

* bring back original sync

* read expired from the response

* remove unused sync url

* read if netRevenue from response, include extra params

* set displaymanager to prebid.js

* update docs

* test is working

* don't merge pixel and iframe syncs

* provide renderer

* lint fix

* remove banner support

* switch to openRTB for response

* use fromORTB to simplify bidder

* don't pass entire bid to renderer

* set video context in ext

* endpoint should end with /

* update documentation unitId

* check if video features are enabled for tests

* fix after review

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Co-authored-by: Michele Nasti <michele.nasti@gmail.com>