(core) Improve API Console and link from Document Settings.

Summary:
Changes to building and serving:
- Remove unpkg dependencies, add npm module for swagger-ui-dist instead.
- Move apiconsole JS logic into core/app/client/apiconsole.ts, and use TypeScript.
- Add symlinks to swagger in static/ and core/static/.
- Refactor loadScript, and add loadCssFile; use these to load swagger-ui resources.

Changes to console itself:
- Support docId, workspaceId, orgId URL parameters. When present, the matching
  value in dropdowns is moved to the front and marked as "(Current)".
- Fix the ordering of example values, particularly for workspaces.
- Remove unwanted example values.
- Hide confusing "Authorize" button.
- Hide API keys, and rely consistently on cookies for executing API calls.

Integration into Grist:
- Added a button to Document Settings, just under document ID in "API".
- The button opens a separate page, passing in org, workspace, and doc info for the current doc.

Test Plan: Only tested manually, no automated tests yet.

Reviewers: jarek

Reviewed By: jarek

Differential Revision: https://phab.getgrist.com/D4173

app/client/lib/loadScript.js

@@ -1,19 +0,0 @@
-const Promise = require('bluebird');
-const G = require('./browserGlobals').get('document');
-
-/**
- * Load dynamically an external JS script from the given URL. Returns a promise that is
- * resolved when the script is loaded.
- */
-function loadScript(url) {
-  return new Promise((resolve, reject) => {
-    let script = G.document.createElement("script");
-    script.type = "text/javascript";
-    script.onload = resolve;
-    script.onerror = reject;
-    script.src = url;
-    G.document.getElementsByTagName("head")[0].appendChild(script);
-  });
-}
-
-module.exports = loadScript;

app/client/lib/loadScript.ts

@@ -0,0 +1,23 @@
+import {dom} from 'grainjs';
+
+/**
+ * Load dynamically an external JS script from the given URL. Returns a promise that is
+ * resolved when the script is loaded.
+ */
+export function loadScript(url: string) {
+  return new Promise((resolve, reject) => {
+    const script = dom("script", {type: "text/javascript", src: url, crossorigin: "anonymous"});
+    document.head.appendChild(Object.assign(script, {onload: resolve, onerror: reject}));
+  });
+}
+
+/**
+ * Load dynamically an external CSS file from the given URL. Returns a promise that is
+ * resolved when the file is loaded.
+ */
+export function loadCssFile(url: string): Promise<void> {
+  return new Promise((resolve, reject) => {
+    const link = dom("link", {rel: "stylesheet", href: url});
+    document.head.appendChild(Object.assign(link, {onload: resolve, onerror: reject}));
+  });
+}