Use explicit type imports

[ezra-sg]

In order to make code more readable and consistent, we should enable the eslint rule https://typescript-eslint.io/rules/consistent-type-imports/ . This will require types to be imported separately from non-types, where currently, we import mixed types and non-types in such a way that by looking at imports, we cannot tell if the thing being imported is a type or something else, like an object or a constant.