(core) Configure more comprehensive eslint rules for Typescript

Summary:
- Update rules to be more like we've had with tslint
- Switch tsserver plugin to eslint (tsserver makes for a much faster way to lint in editors)
- Apply suggested auto-fixes
- Fix all lint errors and warnings in core/, app/, test/

Test Plan: Some behavior may change subtly (e.g. added missing awaits), relying on existing tests to catch problems.

Reviewers: paulfitz

Reviewed By: paulfitz

Differential Revision: https://phab.getgrist.com/D2785

app/gen-server/lib/Housekeeper.ts

@@ -210,7 +210,9 @@ export class Housekeeper {
 
   // Call a document endpoint with a permit, cleaning up after the call.
   // Checks that the user is the support user.
-  private _withSupport(callback: (docId: string, headers: Record<string, string>) => Promise<Fetch.Response>): express.RequestHandler {
+  private _withSupport(
+    callback: (docId: string, headers: Record<string, string>) => Promise<Fetch.Response>
+  ): express.RequestHandler {
     return expressWrap(async (req, res) => {
       const userId = getAuthorizedUserId(req);
       if (userId !== this._dbManager.getSupportUserId()) {