Add mediabrama.md (prebid#4881)

* Add mediabrama.md

* remove TOC

don't need a TOC for such a short doc

* linter fixes

* html tags removed

---------

Co-authored-by: Oleh Naimushyn <ncm.net@gmail.com>
Co-authored-by: bretg <bgorsline@gmail.com>
Co-authored-by: Muki Seiler <muuki88@users.noreply.github.com>

Author: 4 people

dev-docs/bidders/mediabrama.md

@@ -0,0 +1,56 @@
+---
+layout: bidder
+title: MediaBrama
+description: Prebid MediaBrama Bidder Adapter.
+pbjs: true
+pbs: false
+gvl_id: none
+biddercode: mediabrama
+media_types: banner
+gdpr_supported: false
+usp_supported: false
+coppa_supported: false
+schain_supported: false
+safeframes_ok: false
+dchain_supported: false
+deals_supported: false
+floors_supported: true
+fpd_supported: false
+ortb_blocking_supported: false
+multiformat_supported: will-bid-on-one
+prebid_member: false
+---
+
+### Description
+
+MediaBrama header bidding adapter connects with mediabrama demand sources to fetch bids for display placements. Please reach out to your account manager or <support@mediabrama.com> for more information.
+
+### Bid params
+
+{: .table .table-bordered .table-striped }
+| Name         | Scope    | Description                        | Example    | Type     |
+|--------------|----------|------------------------------------|------------|----------|
+| `placementId`| optional | The placement ID from MediaBrama   | `'24428'`  | `string` |
+| `bidFloor`   | optional | Lowest value of expected bid price | `1.1`      | `float`  |
+
+### Test Parameters
+
+300x250 banner test
+
+```javascript
+var adUnits = [{
+  code: 'prebid-place',
+  mediaTypes: {
+    banner: {
+      sizes: [[300, 250]]
+    }
+  },
+  // Replace this object to test a new Adapter!
+  bids: [{
+    bidder: 'mediabrama',
+    params : {
+      placementId : "24428" //test, please replace after test
+    }
+  }]
+}];
+```