Show warning message when VA name is exceed 12 characters

The Jira ticket(Reopened):

https://arraynetworks.atlassian.net/browse/TWSD-1139
I removed original code that is only use attribute (minlength and maxlength) to prevent user input over 12 characters.

I changed the behavior for the VA Name field, it will show warning if user input over 12 characters, and the "Next" button will be disabled,

you can see attachment for reference.
I removed ng-verify="control:'addVAInstanceForm'" it will only prevent some cases based on verify.directive.js,

and it is customized directive previous engineers was written, and the usage cannot fit our requiremnt.

Thus,

I use AngularJS originall verification.

First,

I added ng-maxlength="12" and warning message(I see other pages for reference).

Then I added required to all needed fields.

Lastly, I use ng-disabled="addVAInstanceForm.$invalid" instead of ng-verify="control:'addVAInstanceForm'".