Add nsupdate ACME DNS authenticator to gui

I’d like to see nsupdate as a predefined authenticator instead of having to configure it through the shell. From the outside it looks like this would be a very simple plugin update.

Problem/Justification
(What is the problem you are trying to solve with this feature/improvement or why should it be considered?)
The nsupdate ACME DNS authenticator allows certificate authority verification without exposing any ports of the server to the internet. You only need a publically available DNS server that can accept tsig key verified updates.

Impact
(How is this feature going to impact all TrueNAS users? What are the benefits and advantages? Are there disadvantages?)
It can simplify the configuration of remote dns updates for those using compatible DNS servers. There are no disadvantages to any other users.

User Story
(Please give a short description on how you envision some user taking advantage of this feature, what are the steps a user will follow to accomplish it)
The plugn would look very similar to the existing ones for OVH, route53, and Cloudflare. There are only 4 variable fields for the plugin and it appears to follow the same flow as the existing GUI accessible plugins. Easing access for usage of some self hosted DNS solutions like bind, infoblox, opendns, basically any tsig key update capable DNS server could cover multiple end user cases for minimal work adding the single plugin option.