Add multi-format ad unit support to Beachfront adapter

[jsalis]

Type of change

• Feature
• Does this change affect user-facing APIs or examples documented on http://prebid.org?

Description of change

Adds scoped bidder params for video and banner so that bid requests can be sent for both formats. Previously, only a video bid request would be sent for an ad unit that declared support for video and banner.

    var adUnits = [
        {
            code: 'test-video-banner',
            mediaTypes: {
                video: {
                    context: 'instream',
                    playerSize: [ 640, 360 ]
                },
                banner: {
                    sizes: [ 300, 250 ]
                }
            },
            bids: [
                {
                    bidder: 'beachfront',
                    params: {
                        video: {
                            bidfloor: 0.01,
                            appId: '11bc5dd5-7421-4dd8-c926-40fa653bec76',
                            mimes: [ 'video/mp4', 'application/javascript' ]
                        },
                        banner: {
                            bidfloor: 0.01,
                            appId: '3b16770b-17af-4d22-daff-9606bdf2c9c3'
                        }
                    }
                }
            ]
        }
    ];

prebid/prebid.github.io#763

[snapwich]

LGTM