fix: add missing package.json and source maps (#5040)

* Use --exclude to skip node_modules

Instead of copying and then deleting them.  This will also catch some
node_modules directories that were missed.

* Remove per-extension dependency install

Code packages all the dependencies using webpack for each extension so
there are no dependencies to install.

* Include source maps

I also moved this to its own patch because it feels sufficiently
standalone.

Fixes #5026.

* Refresh language patch

The base is slightly different so it needed to be refreshed.

* Add missing package.json

This was caused by switching to Code's package step which does not
include the package.json.

Fixes #5019.

* Include keytar

It seems this actually is used now.

patches/display-language.diff

@@ -79,7 +79,7 @@ Index: code-server/lib/vscode/src/vs/code/browser/workbench/workbench.html
 +		} catch (error) { /* Probably fine. */ }
  		Object.keys(self.webPackagePaths).map(function (key, index) {
  			self.webPackagePaths[key] = new URL(
- 				`{{VS_BASE}}/static/remote/web/node_modules/${key}/${self.webPackagePaths[key]}`,
+ 				`{{VS_BASE}}/static/node_modules/${key}/${self.webPackagePaths[key]}`,
 @@ -52,7 +76,8 @@
  					return value;
  				}