init appstockSSP Bid Adapter (#6177)

* init appStockSSP Bid Adapter

* review upd

---------

Co-authored-by: Kanceliarenko <kostiantyn.k@teqblaze.com>

Author: AppstockLTD

dev-docs/bidders/appStockSSP.md

@@ -0,0 +1,37 @@
+---
+layout: bidder
+title: AppStockSSP
+description: Prebid AppStockSSP Bidder Adapter
+biddercode: appStockSSP
+gpp_sids: usstate_all
+tcfeu_supported: true
+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-not-bid
+userIds: all
+pbjs: true
+pbs: true
+pbs_app_supported: true
+safeframes_ok: true
+gvl_id: 1223
+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'` |
+| `region`      | optional | Region (for Prebid.js) | `'us-east'` (default) or `'eu'` or `'apac'` | `'string'` |
+
+### Note
+
+For the prebid server and prebid.js you only need to use one parameter: either placementId or endpointId.