[Feature request] Set number of postfix and amavisd processes in iredmail-docker.conf

[bluepuma77]

Process more emails concurrently explains how to increase the number of postfix and amavisd processes in the container.

The config files all have iRedMail comments to not change them manually, that they are managed automatically.

It would be great if we could set the number of processes in the iredmail-docker.conf file.

Example (last line):

mkdir /iredmail      
cd /iredmail
touch iredmail-docker.conf

echo HOSTNAME=mail.mydomain.com >> iredmail-docker.conf
echo FIRST_MAIL_DOMAIN=mydomain.com >> iredmail-docker.conf
echo FIRST_MAIL_DOMAIN_ADMIN_PASSWORD=my-secret-password >> iredmail-docker.conf
echo MLMMJADMIN_API_TOKEN=$(openssl rand -base64 32) >> iredmail-docker.conf
echo ROUNDCUBE_DES_KEY=$(openssl rand -base64 24) >> iredmail-docker.conf
echo POSTFIX_AMAVIS_PROCESS_COUNT=4 >> iredmail-docker.conf

If not set, it should probably default to 1.

[iredmail]

Good idea. Would you like to send a PR? :)