New adapter: Verben (#6442)

* New adapter: Verben

* Apply suggestion from @muuki88

---------

Co-authored-by: Verben <support_trading@verben.com>
Co-authored-by: Muki Seiler <muuki88@users.noreply.github.com>

Author: 3 people

dev-docs/bidders/verben.md

@@ -0,0 +1,35 @@
+---
+layout: bidder
+title: Verben
+description: Prebid Verben Bidder Adapter
+biddercode: verben
+gpp_sids: usstate_all
+tcfeu_supported: false
+usp_supported: true
+coppa_supported: true
+schain_supported: true
+deals_supported: false
+floors_supported: true
+fpd_supported: false
+ortb_blocking_supported: false
+media_types: banner, video, native
+multiformat_supported: will-bid-on-one
+userIds: all
+pbjs: true
+pbs: false
+pbs_app_supported: false
+safeframes_ok: true
+sidebarType: 1
+---
+
+### Bid Params
+
+{: .table .table-bordered .table-striped }
+| Name          | Scope    | Description  | Example                         | Type       |
+|---------------|----------|--------------|---------------------------------|------------|
+| `placementId` | optional | Placement Id | `'0'`                           | `'string'` |
+| `endpointId`  | optional | Endpoint Id  | `'0'`                           | `'string'` |
+
+### Note
+
+For the prebid server and prebid.js you only need to use one parameter: either placementId or endpointId