Drupal: Add Banner fields to Vet Center content type

[davidmpickett]

User Story or Problem Statement

AS A Vet Center editor I NEED be able to add a banner alert to my Vet Center Facility SO THAT I can communicate urgent information to visitors (e.g. closed for hurricane)

Description or Additional Context

This will follow the exact same model as VBA. The same set of fields that were added to the VBA Facility will be added to the Vet Center Facility. The PR for the prior changes as guidance is https://github.com/department-of-veterans-affairs/va.gov-cms/pull/16076

Possible opportunity to harden the repeated set of fields into a Custom Field https://github.com/department-of-veterans-affairs/va.gov-cms/issues/18929

Steps for Implementation

### New Fields to add
- [ ] Display a banner alert on this facility - field_show_banner - Boolean
- [ ] Banner alert headline - field_banner_title - Text (formatted, long)
- [ ] Banner alert message - field_banner_content - Text (formatted, long)
- [ ] Banner alert type - field_alert_type - List (text)
- [ ] Dismissible by user? - field_dismissible_option - List (text)

Acceptance Criteria

• [ ] Banner alert fields appear on Vet Center edit form
• [ ] Banner alert fields can be modified and saved by users with Content Creator - Vet Center and Content Publisher Roles
• [ ] Banner alert fields display the same labels, help text, and character counter settings as appear on VBA Facility content type, and any references to VBA are changed to reference Vet Center
• [ ] GraphQL query is provided on #18925 to expose this field in the FE
• [ ] Requires design review
• [ ] Requires accessibility review

[omahane]

https://github.com/department-of-veterans-affairs/va.gov-cms/pull/16076 is the VBA work that could be a model.

[mmiddaugh]

@Agile6MSkinner we should consider timing - we need to get the business logic nailed down for when it can/should be used and communicate that with editors before this brand new and prominent field is exposed to editors.

[Agile6MSkinner]

@mmiddaugh Definitely. This Drupal story will not expose the banner on the front end, but could confuse editors when the see the fields. I'll get together a CM ticket.