:sparkles: Support showing video from an external sources

[aphexcx]

Useful for supporting any video in, not just cameras. Think resolume, other VJ suites.

Could grab frames, push them into a pixel buffer, and then provide it via the plugin system to any show.

Outstanding work:

• [ ] JVM VideoProvider implementation
• [ ] Pick source (remotely)
• [ ] Push video preview stream to clients
• [x] What does the help code look like? Call with function with injected uv? uniform sampler2D vidIn; vs uniform vec4 vidIn; vs vec4 vidIn(vec2 uvIn);