Fix generation of bundled.json, make source maps work in prod builds

Summary:
This diff fixes several issues around loading plugin, such as:

* make suresource maps work in the flipper-server production build
* make sure default plugins are no symlinked, which wouldn't work anywhere else but on the the system where it was build
* support release channel param for flipper-server

Bundled flipper-server is now 42MB (with icons (see later diffs) and plugins
```
ll flipper-server-v0.0.0.tgz
-rw-r--r--  1 mweststrate  staff    42M 23 Dec 15:29 flipper-server-v0.0.0.tgz
```

Reviewed By: nikoant

Differential Revision: D33294677

fbshipit-source-id: 63538dc8127f883fee6a3608673ad11ce239b350

desktop/flipper-server-core/src/plugins/loadDynamicPlugins.tsx

@@ -45,6 +45,11 @@ export async function loadDynamicPlugins(): Promise<InstalledPluginDetails[]> {
       )
     ).map((p: any) => p.name) as string[],
   );
+  console.log(
+    `✅  Detected ${bundledPlugins.size} bundled plugins: ${Array.from(
+      bundledPlugins,
+    ).join(', ')}.`,
+  );
   const [installedPlugins, unfilteredSourcePlugins] = await Promise.all([
     process.env.FLIPPER_NO_PLUGIN_MARKETPLACE
       ? Promise.resolve([])
@@ -60,23 +65,23 @@ export async function loadDynamicPlugins(): Promise<InstalledPluginDetails[]> {
   const defaultPlugins = await getAllInstalledPluginsInDir(defaultPluginsDir);
   if (defaultPlugins.length > 0) {
     console.log(
-      `✅  Loaded ${defaultPlugins.length} default plugins: ${defaultPlugins
-        .map((x) => x.title)
-        .join(', ')}.`,
+      `✅  Loaded ${defaultPlugins.length} default plugins:\n${defaultPlugins
+        .map((x) => `${x.title}@${x.version}`)
+        .join('\n')}.`,
     );
   }
   if (installedPlugins.length > 0) {
     console.log(
-      `✅  Loaded ${installedPlugins.length} installed plugins: ${Array.from(
-        new Set(installedPlugins.map((x) => x.title)),
-      ).join(', ')}.`,
+      `✅  Loaded ${installedPlugins.length} installed plugins:\n${Array.from(
+        new Set(installedPlugins.map((x) => `${x.title}@${x.version}`)),
+      ).join('\n')}.`,
     );
   }
   if (sourcePlugins.length > 0) {
     console.log(
-      `✅  Loaded ${sourcePlugins.length} source plugins: ${sourcePlugins
-        .map((x) => x.title)
-        .join(', ')}.`,
+      `✅  Loaded ${sourcePlugins.length} source plugins:\n${sourcePlugins
+        .map((x) => `${x.title} - ${x.dir}`)
+        .join('\n')}.`,
     );
   }
   return [...defaultPlugins, ...installedPlugins, ...sourcePlugins];