Dismissible Alert for HER demo site

[ekansa]

Hi!

We've got a request to add a dismissible alert to the HER demo site landing page / home page. It should be something like a "modal" that appears by default when a user first accesses the home page, and can then be dismissed / closed.

The text of the alert should say something like (I'm sure we'll need to update it, but that should be simple once the alert is installed):

Welcome to this Arches demonstration site, managed by the Getty Conservation Institute! This demo showcases Arches for HERs, which includes Historic England’s customizations and use of Arches to support cultural heritage consultation and planning processes. It is currently running on an older version of the software (Arches Version 6), and planned updates will improve the performance of this demo. Until then, thank you for your patience!

Disclaimer: The sample data provided here is strictly for software evaluation purposes only.

[ekansa]

@aarongundel FYI