[next] Add support for embed (#1762)

* Move talk-server/config to talk-common/config

* Refactor build into /src/core/build and use common config

* Add embed webpack config

* Start implementing embed

* Implement embed

* Add pym types

* Add event emitter to Talk Context

* Add MatchMedia test for passing values from the context

* Add support for click far away

* Integrate pym click events to registerClickFarAway

* Add tests

* Resolve merge issues

* Apply PR review

src/core/client/embed/PymControl.ts

@@ -0,0 +1,41 @@
+import pym from "pym.js";
+
+import { CleanupCallback, Decorator } from "./decorators";
+
+interface PymControlConfig {
+  id: string;
+  url: string;
+  title: string;
+  decorators?: ReadonlyArray<Decorator>;
+}
+
+export default class PymControl {
+  private pym: pym.Parent;
+  private cleanups: CleanupCallback[];
+
+  constructor(config: PymControlConfig) {
+    const decorators = config.decorators || [];
+
+    this.pym = new pym.Parent(config.id, config.url, {
+      title: config.title,
+      id: `${config.id}_iframe`,
+      name: `${config.id}_iframe`,
+    });
+
+    this.cleanups = decorators
+      .map(enhance => enhance(this.pym))
+      .filter(cb => cb) as CleanupCallback[];
+  }
+
+  public sendMessage(id: string, raw?: string) {
+    this.pym.sendMessage(id, raw || "");
+  }
+
+  public remove() {
+    this.cleanups.forEach(cb => cb());
+    this.cleanups = [];
+
+    // Remove the pym parent.
+    this.pym.remove();
+  }
+}