Support handling deeplinks in plugins

Summary:
This adds support for handling incoming deeplinks in a Sandy plugin, which can be done by using a `client.onDeepLink(deepLink => { } )` listener

Also generalized deeplinks to not just support strings, but also richer objects, which is beneficial to plugin to plugin linking.

Reviewed By: jknoxville

Differential Revision: D22524749

fbshipit-source-id: 2cbe8d52f6eac91a1c1c8c8494706952920b9181

desktop/plugins/logs/index.tsx

@@ -438,11 +438,11 @@ export default class LogTable extends FlipperDevicePlugin<
   };
 
   calculateHighlightedRows = (
-    deepLinkPayload: string | null,
+    deepLinkPayload: unknown,
     rows: ReadonlyArray<TableBodyRow>,
   ): Set<string> => {
     const highlightedRows = new Set<string>();
-    if (!deepLinkPayload) {
+    if (typeof deepLinkPayload !== 'string') {
       return highlightedRows;
     }