Add Open VSX default and an env var for marketplace, fix old marketplace

Our old marketplace only supports `serviceUrl` but this causes the marketplace
to be disabled entirely so this moves the template var check to fix that.

This also removes serverRootPath from the web extension route because that will
include the commit.  When you update code-server (including this update) the web
extension will continue using the old path since it is stored in the browser but
the path will 404 because the commit no longer matches.  This change is only to
support current installations though because this patch also removes the
in-between and has web extensions install directly from the marketplace.

This can be tested by setting EXTENSIONS_GALLERY set to:

    '{"serviceUrl": "https://extensions.coder.com/api"}'


Index: code-server/lib/vscode/src/vs/platform/product/common/product.ts
===================================================================
--- code-server.orig/lib/vscode/src/vs/platform/product/common/product.ts
+++ code-server/lib/vscode/src/vs/platform/product/common/product.ts
@@ -53,6 +53,16 @@ else if (typeof require?.__$__nodeRequir
 			version: pkg.version
 		});
 	}
+
+	Object.assign(product, {
+		extensionsGallery: env.EXTENSIONS_GALLERY ? JSON.parse(env.EXTENSIONS_GALLERY) : (product.extensionsGallery || {
+			serviceUrl: "https://open-vsx.org/vscode/gallery",
+			itemUrl: "https://open-vsx.org/vscode/item",
+			resourceUrlTemplate: "https://open-vsx.org/vscode/asset/{publisher}/{name}/{version}/Microsoft.VisualStudio.Code.WebResources/{path}",
+			controlUrl: "",
+			recommendationsUrl: "",
+		})
+	});
 }
 
 // Web environment or unknown
Index: code-server/lib/vscode/src/vs/server/node/webClientServer.ts
===================================================================
--- code-server.orig/lib/vscode/src/vs/server/node/webClientServer.ts
+++ code-server/lib/vscode/src/vs/server/node/webClientServer.ts
@@ -111,7 +111,7 @@ export class WebClientServer {
 		const serverRootPath = getRemoteServerRootPath(_productService);
 		this._staticRoute = `${serverRootPath}/static`;
 		this._callbackRoute = `${serverRootPath}/callback`;
-		this._webExtensionRoute = `${serverRootPath}/web-extension-resource`;
+		this._webExtensionRoute = `/web-extension-resource`;
 	}
 
 	/**
@@ -312,14 +312,7 @@ export class WebClientServer {
 				codeServerVersion: this._productService.codeServerVersion,
 				rootEndpoint: base,
 				embedderIdentifier: 'server-distro',
-				extensionsGallery: this._webExtensionResourceUrlTemplate ? {
-					...this._productService.extensionsGallery,
-					'resourceUrlTemplate': this._webExtensionResourceUrlTemplate.with({
-						scheme: 'http',
-						authority: remoteAuthority,
-						path: `${this._webExtensionRoute}/${this._webExtensionResourceUrlTemplate.authority}${this._webExtensionResourceUrlTemplate.path}`
-					}).toString(true)
-				} : undefined
+				extensionsGallery: this._productService.extensionsGallery,
 			},
 			callbackRoute: this._callbackRoute
 		};
Index: code-server/lib/vscode/src/vs/platform/extensionResourceLoader/common/extensionResourceLoader.ts
===================================================================
--- code-server.orig/lib/vscode/src/vs/platform/extensionResourceLoader/common/extensionResourceLoader.ts
+++ code-server/lib/vscode/src/vs/platform/extensionResourceLoader/common/extensionResourceLoader.ts
@@ -16,7 +16,6 @@ import { getServiceMachineId } from 'vs/
 import { IStorageService } from 'vs/platform/storage/common/storage';
 import { TelemetryLevel } from 'vs/platform/telemetry/common/telemetry';
 import { getTelemetryLevel, supportsTelemetry } from 'vs/platform/telemetry/common/telemetryUtils';
-import { getRemoteServerRootPath } from 'vs/platform/remote/common/remoteHosts';
 
 export const WEB_EXTENSION_RESOURCE_END_POINT = 'web-extension-resource';
 
@@ -60,7 +59,7 @@ export abstract class AbstractExtensionR
 		private readonly _environmentService: IEnvironmentService,
 		private readonly _configurationService: IConfigurationService,
 	) {
-		this._webExtensionResourceEndPoint = `${getRemoteServerRootPath(_productService)}/${WEB_EXTENSION_RESOURCE_END_POINT}/`;
+		this._webExtensionResourceEndPoint = `/${WEB_EXTENSION_RESOURCE_END_POINT}`;
 		if (_productService.extensionsGallery) {
 			this._extensionGalleryResourceUrlTemplate = _productService.extensionsGallery.resourceUrlTemplate;
 			this._extensionGalleryAuthority = this._extensionGalleryResourceUrlTemplate ? this._getExtensionGalleryAuthority(URI.parse(this._extensionGalleryResourceUrlTemplate)) : undefined;