use specified DNS accounts per domain, is it possible ?

We use acme.sh + acme-dns. acme-dns allows only two TXT records per its account/subdomain. Now we need to specify 3-4 SANs in a single LE certificate. Command looks like this:

```
command: >
acme.sh
--issue
--dns dns_acmedns
--always-force-new-domain-key
-d {{ item.domains | join(' -d ') }}
--cert-file "/nginx-root/{{ item.name }}/cert.pem"
--key-file "/unencrypted-keys/{{ item.name }}/key.pem"
--fullchain-file "/nginx-root/{{ item.name }}/fullchain.pem"
--reloadcmd "..."
```
this commans is executed in docker container. There are environment variables ACMEDNS_BASE_URL, ACMEDNS_USERNAME, ACMEDNS_PASSWORD, ACMEDNS_SUBDOMAIN. All works until `item.domains` contains 1-2 domains. If it contains 3 or more domains acme.sh failed to issue cert after timeout (~20 minutes). When it tries to do get cert I can see only two TXT record in acme-dns but I expected to see 3 or more.

Then I fount that acme-dns does "Rolling update of two TXT records" per account.When creating new account it creates just two empty TXT records in its database and these records are updated by rolling update - no new records are created, just two with rolling update.

So I would like from acme.sh the ability to specify DNS account config per domain and also use the default configuration if per-domain config is not specified.
Is it possible ?

Start by reproducing with the provided `acme.sh --issue --dns dns_acmedns ...` command using 3+ domains instead of 1-2. Next locate the `dns_acmedns` execution path and where `ACMEDNS_BASE_URL`, `ACMEDNS_USERNAME`, `ACMEDNS_PASSWORD`, and `ACMEDNS_SUBDOMAIN` are consumed to confirm whether only one account context is supported. Then run the same containerized flow and compare expected DNS TXT records versus actual acme-dns updates. Done means certificate issuance succeeds reliably for >2 SANs with per-domain (or default-fallback) account behavior, or there is a clear documented limitation.

Scritto dal modello di indicizzazione a partire dal testo della issue.