Proposal to add a Option field for REST API TTL

[eabquina]

For a general use case where a customer wants to set a specific cache TTL for WP REST API endpoints, we add a specific field for the REST API TTL value

Alternatively, we can implement a custom plugin to set specific cache headers for these endpoints too, but that will be covered by another proposal or docs guide

The intention here is to avoid modifying wp-config.php to achieve this, and specifically for those who want to disable cache for

[nullvariable]

@eabquina This looks solid to me. Do other plugins like the Fastly plugin cover this feature? Is there still a need for this?