Add new Adapter: TrafficGate (#3711)

* Add new Adapter: TrafficGate

* New Adapter: TrafficGate

* TrafficGate adapter: add pbjs

* TrafficGate adapter: add flags

Co-authored-by: vlad <vlaktionov@decenterads.com>

dev-docs/bidders/trafficgate.md

@@ -0,0 +1,33 @@
+---
+layout: bidder
+title: TrafficGate
+description: Prebid TrafficGate Bidder Adaptor
+pbs: true
+pbjs: true
+biddercode: trafficgate
+media_types: banner, video, native, audio
+gdpr_supported: true
+pbs_app_supported: true
+multiformat_supported: will-bid-on-any
+usp_supported: true
+schain_supported: false
+coppa_supported: true
+dchain_supported: false
+deals_supported: true
+floors_supported: false
+fpd_supported: false
+prebid_member: true
+---
+
+### Note:
+
+The TrafficGate Bidding adapter requires setup before beginning. Please contact us at support@bidscube.com
+
+### Bid Params
+
+{: .table .table-bordered .table-striped }
+| Name          | Scope    | Description  | Example     | Type     |
+|---------------|----------|--------------|-------------|----------|
+| `placementId` | required | Placement ID | `'12345'`   | `string` |
+|---------------|----------|--------------|-------------|----------|
+| `host`        | required | Host         | `'example'` | `string` |