Add client side form validation

[AlstonLin]

More efficient for the server and better UX. Use the default MDL error UI to show errors. See SelectField for an example of this.

First, build a custom class called FieldValidationError.

This should be how it works

• The field should handle checking of itself, with props giving the abilities for their users to customize constraints
• If there is an error, the widget should update it's own UI and throw a FieldValidationError when getting the value
• The users of them form should catch these FieldValidationError and simply return if it caught, stopping any further action.

[AlstonLin]

Here's a problem with this approach - since it will throw an error, this will only allow a single field to be validated and update the UI. If there's multiple errors, then only the first one will be shown.

We should figure out a different way to approach this