Reuse STATIC_HOST in assets/textures loader in replay_detail.html

[Jerome Leclanche]

The following should reuse settings.STATIC_HOST:

         Joust.viewer('joust-container')
             .metadata(cb)
             .assets("//static.hsreplay.net/static/joust/assets/")
             .textures("//static.hsreplay.net/static/joust/textures/")
             .fromUrl('{{ replay_data_url }}');