Add validation to the scheme dashboard panels and deploy-dao page

Add validation to the scheme dashboard panels and deploy-dao page. When the use enters and invalid value, or fails to enter a required value, prevent submission of the form and feedback with a message describing how to correct the problem.

arc-js already does much of what is required of the scheme dashboard panels, and Alchemy reports the errors as snacks, but we want something more immediate to the form that happens before submission to arc-js.

Use Aurelia-Validation.

Start with the scheme dashboard panels and the deploy-dao page, then read how arc-js currently validates their forms and how Alchemy surfaces errors as snacks. Review Aurelia-Validation's form-validation behavior and identify the required and invalid-value cases. Done means invalid submissions are blocked and each problem receives immediate corrective feedback before arc-js submission.

Written by the indexing model from the issue text.