wk1: initial docker image setup

target/dovecot/auth-checkpassword.conf.ext

@@ -0,0 +1,21 @@
+# Authentication for checkpassword users. Included from 10-auth.conf.
+#
+# <doc/wiki/AuthDatabase.CheckPassword.txt>
+
+passdb {
+  driver = checkpassword
+  args = /usr/bin/checkpassword
+}
+
+# passdb lookup should return also userdb info
+userdb {
+  driver = prefetch
+}
+
+# Standard checkpassword doesn't support direct userdb lookups.
+# If you need checkpassword userdb, the checkpassword must support
+# Dovecot-specific extensions.
+#userdb {
+#  driver = checkpassword
+#  args = /usr/bin/checkpassword
+#}