refactor: Significantly refactor how conditions work internally (#1886)

- Much improved API cleanliness and testability to allow further
extensibility in future
 - Simplified code in `live` view

This technically contains a small change in how overrides work in the
`live` view. Since that change is _closer_ to the documentation, and
since this is likely to be rarely used, this is not considered a
breaking change. Previously, overrides for a given live camera would
always render _as if_ that camera was selected, vs was actually
selected. Now, overrides will only apply in the live view when the
camera is _actually_ selected. If this is an issue for you in practice,
lets discuss.

src/card-controller/hass/hass-manager.ts

@@ -46,12 +46,10 @@ export class HASSManager {
     const oldHass = this._hass;
     this._hass = hass;
 
-    if (this._api.getConditionsManager().hasHAStateConditions()) {
-      this._api.getConditionsManager().setState({
-        state: this._hass.states,
-        user: this._hass.user,
-      });
-    }
+    this._api.getConditionStateManager().setState({
+      state: this._hass.states,
+      user: this._hass.user,
+    });
 
     // Theme may depend on HASS.
     this._api.getStyleManager().applyTheme();