(core) Faster builds all around.

Summary:
Building:
- Builds no longer wait for tsc for either client, server, or test targets. All use esbuild which is very fast.
- Build still runs tsc, but only to report errors. This may be turned off with `SKIP_TSC=1` env var.
- Grist-core continues to build using tsc.
- Esbuild requires ES6 module semantics. Typescript's esModuleInterop is turned
  on, so that tsc accepts and enforces correct usage.
- Client-side code is watched and bundled by webpack as before (using esbuild-loader)

Code changes:
- Imports must now follow ES6 semantics: `import * as X from ...` produces a
  module object; to import functions or class instances, use `import X from ...`.
- Everything is now built with isolatedModules flag. Some exports were updated for it.

Packages:
- Upgraded browserify dependency, and related packages (used for the distribution-building step).
- Building the distribution now uses esbuild's minification. babel-minify is no longer used.

Test Plan: Should have no behavior changes, existing tests should pass, and docker image should build too.

Reviewers: georgegevoian

Reviewed By: georgegevoian

Subscribers: alexmojaki

Differential Revision: https://phab.getgrist.com/D3506

app/common/UserAPI.ts

@@ -9,13 +9,13 @@ import {OrgUsageSummary} from 'app/common/DocUsage';
 import {Product} from 'app/common/Features';
 import {ICustomWidget} from 'app/common/CustomWidget';
 import {isClient} from 'app/common/gristUrls';
-import {FullUser} from 'app/common/LoginSessionAPI';
+import {FullUser, UserProfile} from 'app/common/LoginSessionAPI';
 import {OrgPrefs, UserOrgPrefs, UserPrefs} from 'app/common/Prefs';
 import * as roles from 'app/common/roles';
 import {addCurrentOrgToPath} from 'app/common/urlUtils';
 import {encodeQueryParams} from 'app/common/gutil';
 
-export {FullUser} from 'app/common/LoginSessionAPI';
+export type {FullUser, UserProfile};
 
 // Nominal email address of the anonymous user.
 export const ANONYMOUS_USER_EMAIL = 'anon@getgrist.com';
@@ -285,8 +285,6 @@ export interface DocStateComparisonDetails {
   rightChanges: ActionSummary;
 }
 
-export {UserProfile} from 'app/common/LoginSessionAPI';
-
 export interface UserAPI {
   getSessionActive(): Promise<ActiveSessionInfo>;
   setSessionActive(email: string): Promise<void>;