Check TOS

What would you like to have changed?

Either expose ACMEManager.newACMEClientWithAccount, add this initialization in ACMEManager.PreCheck with the same interactive flag, or add a new function altogether to manually InitializeAccount.

Why is this feature a useful, necessary, and/or important addition to this project?

The goal is to have a check whether or not the cached account has accepted the TOS, or if in interative mode, prompt the user to accept/decline with the link to the TOS. Fetching and exposing the Acme meta directory would also be useful. I am nut sure which approach makes more sense in the given flow, but I am leaning towards separating the TOS code in https://github.com/caddyserver/certmagic/blob/b6b3db32bcd5f87d56bc0fba1db708499259653a/acmeclient.go#L70-L123
and adding another function to initialize the account (interactively, error if not accepted) or check Account.TermsOfServiceAgreed if already exists.

I will try to write a PR with this idea if you think it's ok.

Start with the ACME account and TOS handling in acmeclient.go, especially the referenced section, and inspect the ACMEManager.PreCheck flow and any existing Account.TermsOfServiceAgreed handling. The desired behavior is a check for cached-account TOS acceptance, with interactive prompting and a TOS link when needed; completion requires choosing and implementing a clear initialization or checking API.