Ability to set preferred DNS TTL when using APIs

[d19dotca]

Currently Cloudron runs with the lowest allowed TTL dependent on each DNS service it integrates with. Previous discussions in the forum and various resources online had indicated that the lowest TTL isn't always the wisest (even though it's normally totally fine in most cases), so I'd like to request that Cloudron add a way to set a preferred TTL for the domains, and when manually running a Sync DNS that it change the Cloudron-controlled DNS records to match the desired TTL set by the admin.