Show viewer count

[cogwheel]

[Alex-451]

Where should it show the viewer count?

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@TimmmyGotPasion It will go in the "dock" window that appears after signing in to Caffeine (see https://github.com/caffeinetv/obs-studio/blob/integration/UI/window-caffeine.hpp)

This will have to wait until caffeinetv/libcaffeine#52 is finished since the viewer count data comes through a websocket.