Added: Initial support for shared mailboxes

target/dovecot/11-shared.conf

@@ -0,0 +1,53 @@
+# Example shared namespace configuration
+#<## <-- '#<#' indicates comment characters that are safe to be auto-removed
+#<## by the setup script under certain conditions (when inbox sharing is on)
+
+#<#namespace {
+#<#  type = shared
+#<#  @DOVECOT_NAMESPACE_SEPARATOR_CLAUSE@
+#<#
+#<#  # Mailboxes are visible under "shared/user@domain/"
+#<#  # %%n, %%d and %%u are expanded to the destination user.
+#<#  prefix = shared/%%u/
+#<#
+#<#  # Mail location for other users' mailboxes. Note that %variables and ~/
+#<#  # expands to the logged in user's data. %%n, %%d, %%u and %%h expand to the
+#<#  # destination user's data.
+#<#  location = maildir:%%h:INDEX=~/shared/%%u:INDEXPVT=~/shared/%%u
+#<#
+#<#  subscriptions = yes
+#<#
+#<#  # List the shared/ namespace only if there are visible shared mailboxes.
+#<#  list = children
+#<#}
+#<## Should shared INBOX be visible as "shared/user" or "shared/user/INBOX"?
+#<#mail_shared_explicit_inbox = no
+#<#
+#<#
+#<## The ACL plugin is needed for access definitions
+#<#mail_plugins = acl
+#<#protocol imap {
+#<#  mail_plugins = $mail_plugins acl imap_acl
+#<#}
+#<#
+#<#
+#<## This is a suitable default ACL setting
+#<#plugin {
+#<#  # Without global ACLs:
+#<#  acl = vfile
+#<#
+#<#  # With global ACL files in /etc/dovecot/dovecot-acls file (v2.2.11+):
+#<#  # acl = vfile:/etc/dovecot/dovecot-acl
+#<#
+#<#  # If enabled, don't try to find dovecot-acl files from mailbox directories.
+#<#  # This reduces unnecessary disk I/O when only global ACLs are used. (v2.2.31+)
+#<#  # acl_globals_only = yes
+#<#}
+
+
+# You need a dictionary to advertise shared inboxes to clients.
+# Dictionaries can have various backends.
+# You will probably want to customize this, so the dictionary is persistent.
+# plugin {
+# acl_shared_dict = file:/var/mail/dictionary/dict-acl
+# }