MoPub Sample App

Jun 16, 2020

- Remove Moat and IAS measurement SDKs.
- Consolidate banners, interstitials, and rewarded ads into one container. Third party network adapters for these formats should now extend `BaseAd`.
- Consolidate the `mopub-sdk-interstitial` and `mopub-sdk-rewarded-video` modules into `mopub-sdk-fullscreen`.
- Upgrade to use the Androidx Media2 video player for VAST videos.