Add typescript eslint rules

Describe the problem

The lack of eslint rules for the declaration files allow the type declarations to be inconsistent, specifically preferring interfaces over types or vice-versa and using the method notation (name(): ReturnType) over the function field notation (name: () => ReturnType).

Describe the proposed solution

Installing the typescript eslint packages to enforce style rules.

Alternatives considered

No response

Importance

nice to have

Additional Information

No response