Re-enable `@typescript-eslint/naming-convention`

There are 514 violations when I remove the override that turns this rule off and run `yarn eslint . --cache --ext js,ts --quiet`.

There are four types of violations:

- Enum members that should be `PascalCase`
- Type parameters that should be more than one character
- Property names that should be `camelCase`, `PascalCase` or `UPPER_CASE`
- Variable names that should be `camelCase`, `PascalCase` or `UPPER_CASE`

Other than variable names, these would cause backward-incompatible changes, so we may want to handle them by adding overrides at the violation site with a comment such as:

``` typescript
// This rule was added after this code was in place;
// we are keeping this name for backward compatibility
// eslint-disable-next-line @typescript-eslint/naming-convention
```

Start by removing the override for @typescript-eslint/naming-convention and run `yarn eslint . --cache --ext js,ts --quiet` to inspect the 514 violations. Group findings by enum members, type parameters, properties, and variables; preserve incompatible public names with targeted eslint comments where needed. Done means the lint command passes with the rule enabled.

Written by the indexing model from the issue text.