(core) Add rules to eslint to better match our coding conventions.

Summary:
We used tslint earlier, and on switching to eslint, some rules were not
transfered. This moves more rules over, for consistent conventions or helpful
warnings.

- Name private members with a leading underscore.
- Prefer interface over a type alias.
- Use consistent spacing around ':' in type annotations.
- Use consistent spacing around braces of code blocks.
- Use semicolons consistently at the ends of statements.
- Use braces around even one-liner blocks, like conditionals and loops.
- Warn about shadowed variables.

Test Plan: Fixed all new warnings. Should be no behavior changes in code.

Reviewers: paulfitz

Reviewed By: paulfitz

Differential Revision: https://phab.getgrist.com/D2831

app/server/lib/RowAccess.ts

@@ -27,7 +27,7 @@ export function getRelatedRows(docActions: DocAction[]): ReadonlyArray<readonly
     if (docAction[0] === 'RenameTable') {
       if (addedTables.has(currentTableId)) {
         addedTables.delete(currentTableId);
-        addedTables.add(docAction[2])
+        addedTables.add(docAction[2]);
         continue;
       }
       tableIds.delete(currentTableId);