(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

buildtools/tsconfig-base.json

@@ -21,7 +21,7 @@
     },
     "composite": true,
     "plugins": [{
-      "name": "typescript-tslint-plugin"
+      "name": "typescript-eslint-language-service"
     }],
     "emitDecoratorMetadata": true,
     "experimentalDecorators": true,