Axinom DRM "Bearer" authorization license server proxy

Implements the license request authorization protocol described in Dash-Industry-Forum/DASH-IF-IOP#300 and forwards license requests to the real Axinom DRM testing license server.

This is a temporary solution that can be used for R&D until the Axinom DRM license server itself supports the DASH-IF mechanism.

This software is deployed to https://axinom-drm-bearer-token-proxy.azurewebsites.net and may be used via the following URLs:

• https://axinom-drm-bearer-token-proxy.azurewebsites.net/PlayReady/AcquireLicense
• https://axinom-drm-bearer-token-proxy.azurewebsites.net/Widevine/AcquireLicense
• https://axinom-drm-bearer-token-proxy.azurewebsites.net/FairPlay/AcquireLicense