[Spike] Validation of inputs (frontend & backend)

[kaiNext]

Frontend
Built-in form validation (using HTML5 form validation features)

Backend

The risk of NoSQL injection is mitigated with the use of mongoose which takes care of validating user input for expected types.
Using @hapi/joi may provide additional protection; however, a separate schema for joi may need to be maintained (i.e. repeating the schema already set up for mongoose)