* chore: Drop management of `SASLAUTHD_*` ENV
- `variables-stack.sh` does not need to manage all these extra ENV or store them. They're not used anywhere else.
- `saslauthd.sh` is the only consumer of these ENV which are effectively direct key/value mappings, with some defaults provided / inherited.
Instead of trying to conditionally support key/value pairs when ENV is set, we could instead use `sed` to delete lines with empty values.
* chore: Drop fallbacks + update configs to match docs
- Drop deprecated support:
- `DOVECOT_HOSTS` is an ENV deprecated since v10.
- Fallback for missing URI scheme introduced for Dovecot and SASLAuthd in v10.
- Adding error log message when no LDAP URI scheme is detected for the supported ENV (when set).
- Docs updated for ENV to reflect the mandatory requirement. `mailserver.env` partially synced equivalent sections.
- Provided base LDAP configs (for overriding) likewise updated from `domain.com` to `example.com`.
- LDAP test updated for required `ldap://` URI scheme. Common ENV shared across LDAP configs hoisted out of the Postfix group.
* chore: Remove unset lines in generated `saslauthd.conf`
