[DOC] - update and enhance FSA info

[hey-august]

Describe the requested update
Tammie requested a page on the FreeSWITCH or SignalWire docs explaining the difference between FreeSWITCH and FreeSWITCH Advantage.

It may be appropriate to have a resource in both docs sites.

Reason for the request
Status quo is confusing for customers. The info that's there is extremely out of date and not helpful.

For example: https://developer.signalwire.com/freeswitch/FreeSWITCH-Explained/Enterprise-Deployment/

Sections to be updated

• Enterprise deployment