add gateway config

[osnet]

This is the original configfile from bitbucket. Just add this to the app-conf volume and IMAP will be available

# See the kopano-gateway.cfg(5) manpage for details and more directives.

# Space-separated list of address:port specifiers with optional %interface
# infix for where the server should listen for connections.
# imaps is normally on 993, pop3s on 995.
#
#pop3_listen = *%lo:110
#pop3s_listen =
imap_listen = 0.0.0.0:143
#imaps_listen = 0.0.0.0:993
# File with RSA key for SSL
#ssl_private_key_file = /etc/kopano/gateway/privkey.pem
#File with certificate for SSL
#ssl_certificate_file = /etc/kopano/gateway/cert.pem

# Disable all plaintext authentications unless SSL/TLS is used
#disable_plaintext_auth = no
# Verify client certificate
#ssl_verify_client = no
# Client verify file and/or path
#ssl_verify_file =
#ssl_verify_path =
#tls_min_proto = tls1.2

# Connection to the storage server.
# Please refer to the administrator manual or manpage why HTTP is used rather than the UNIX socket.
server_socket = http://localhost:236/
# Bypass authentification when connecting as an administrator to the UNIX socket.
bypass_auth = yes

# Whether to show the hostname in the logon greeting to clients.
server_hostname_greeting = no
# Override own DNS name for presentation in the protocol greeting line.
#server_hostname =

#log_method = auto
# Loglevel (0(none), 1(crit), 2(err), 3(warn), 4(notice), 5(info), 6(debug))
log_level = 3
log_file = -
log_timestamp = yes

# Only mail folder for IMAP or all subfolders (calendar, contacts, tasks, etc. too)
imap_only_mailfolders = yes
# Show Public folders for IMAP
imap_public_folders = yes
# The maximum size of an email that can be uploaded to the gateway
imap_max_messagesize = 128M

[osnet]

double post due to false positive 404