[Events] [FE & CMS Design] Enable Facility Editors to publish events to multiple facilities

[wesrowe]

Description

User story

AS A VAMC Editor with access to one or more VAMCs
I WANT the options to publish an event to one or more of my VAMCs AND the Outreach events calendar
SO THAT I can promote the event where I think most appropriate.

Improvements that would be nice to include here:

• Main one: use the new CMS multi-select component (when ready) to enable a more intuitive, checkbox-style multi-select for facilities
• Filter facilities to only show the ones the Editor has permission for
• Work with engineering to get an approved plan for handling breadcrumbs
• Ensure "Outreach events calendar" is only available in one place: either the dropdown or the separate checkbox designed in CMS Design: Enable Facility Editors to publish events to the National Outreach Calendar #14788.

Acceptance criteria

• Design provided that allows Editors to publish an Event to multiple Sections / VAMCs
• FE breadcrumbs are considered and design is reviewed with FE engineers / Drupal engineers
• BE: Enable an Event to be published to multiple facility Events lists #15295 is updated with final design file