refactor(packages): dry up core, html, and react UI architecture (#699)

packages/html/src/ui/controls/context.ts

@@ -0,0 +1,11 @@
+import type { ControlsState, StateAttrMap } from '@videojs/core';
+import { createContext } from '@videojs/element/context';
+
+export interface ControlsContextValue {
+  state: ControlsState;
+  stateAttrMap: StateAttrMap<ControlsState>;
+}
+
+const CONTROLS_CONTEXT_KEY = Symbol('@videojs/controls');
+
+export const controlsContext = createContext<ControlsContextValue>(CONTROLS_CONTEXT_KEY);