changelog: * add `noinlines` option * add `noreplies` option * ignore only notices * support sending emails over SMTP relay by @n.bouma * fix metadata saving on failed deliveries * fix email queuing and resending (mostly in case of graylisting enabled on the recipient's server) * migrated to mautrix-go > 0.15.x * properly work with synapse retention policy * automatically remove known forwarding addresses from the list of reply recipients * shared secret auth support by @JeWe37 * add `spam:list`, `spam:add`, `spam:remove`, `spam:reset` commands (replace the only `spamlist` option) * rearrange help message * update readme with the full list of supported commands new env vars: * POSTMOOGLE_SHAREDSECRET * POSTMOOGLE_MAILBOXES_FORWARDED * POSTMOOGLE_RELAY_HOST * POSTMOOGLE_RELAY_PORT * POSTMOOGLE_RELAY_USERNAME * POSTMOOGLE_RELAY_PASSWORD removed env vars: * POSTMOOGLE_NOENCRYPTION