[WIP] First pass on form outline

Some firefox issues regarding on the .form__input-container and issues
with input[type=“search”]
Fix outline issues in Firefox and input search

Also remove temporary csslint comments
Focus outline now appears on errored input state
Split input height properties into own placeholder so we can use %form-input on <textarea>
Merge pull request #86 from moneyadviceservice/outline-focus

Form input focus state