Add support for wildcard subdomains

**Is your feature request related to a problem? Please describe.**
Currently, there is no way to set up a multi-tenant web app using Azure static sites that uses one domain per tenant.

**Describe the solution you'd like**
Ideally, I'd like to be able to set up a wildcard domain entry (for example *.saas.app). That way I can run one subdomain per tenant in my multi-tenant SAAS application for example:

- https://tenant1.saas.app
- https://tenant2.saas.app

Failing this if the subdomain limit could be removed, it would also solve the problem. These are not multiple websites, just different ways of accessing the same site. Ideally, we shouldn't be billed extra for this. With app services, there are multiple methods to support this.

**Describe alternatives you've considered**
Currently, we use Azure static websites instead and create a subdomain entry on the CDN per tenant. This is not ideal as creating each sub-domain is time-consuming.

This is currently a blocker for us adopting Azure static web apps for a couple of our projects.