_serviceBrand is only used for typing and should not result in emit

Also adds readonly

This reverts commit 40559425.

This reverts commit a2bc061b.

Revert "merge metadata into local extension"

This reverts commit b354b435.

* Add vscode-webview-resource protocol

Adds a new protocol (`vscode-webview-resource`) for loading resources insides of webviews. This replaces the existing `vscode-resource` protocol and is registered on the main thread instead of in each renderer

This change also adds some rewriting logic to update any `vscode-resource:` references found in the main html to use `vscode-webview-resource` instead.

* Move webview protcol provider to own file

* Remove registration of vscode-resource scheme

* Remove use or parition for each webview

Now that we have a single shared protocol handler, we do not need to run each webview in its own partition

* Fix rewriting csp to use new protocol

* Update src/vs/code/electron-main/app.ts
Co-authored-by: NBenjamin Pasero <benjpas@microsoft.com>
Co-authored-by: NBenjamin Pasero <benjpas@microsoft.com>

Install extensions though drag&drop on the extensions viewlet

Rewrites a few of the remaining calls to `SyncActionDescriptor.create` to use the new `SyncActionDescriptor.from` helper

* Add SyncActionDescriptor.from

There are a whole lot of places in our code where have the following pattern:

```
actionRegistry.registerWorkbenchAction(SyncActionDescriptor.create(CreateNewLocalTerminalAction, CreateNewLocalTerminalAction.ID, CreateNewLocalTerminalAction.LABEL));
```

Notice how the class name has to be repeated  three times.

This change introduces a helper function `SyncActionDescriptor.from` that lets you instead just pass in the class:

```js
actionRegistry.registerWorkbenchAction(SyncActionDescriptor.create(CreateNewLocalTerminalAction));
```

* Avoid cast