(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

buildtools/webpack.config.js

@@ -13,6 +13,7 @@ module.exports = {
   entry: {
     main: "app/client/app",
     errorPages: "app/client/errorMain",
+    apiconsole: "app/client/apiconsole",
     billing: "app/client/billingMain",
     // Include client test harness if it is present (it won't be in
     // docker image).