Add 'dis' component

This commit adds a new 'dis' component to the distillery that serves a
list of all known instances for the moment.

core/flags.go

@@ -0,0 +1,8 @@
+package core
+
+// Flags are global flags for the wdcli executable
+type Flags struct {
+	ConfigPath string `short:"c" long:"config" description:"Path to distillery configuration file"`
+
+	InternalInDocker bool `long:"internal-in-docker" description:"Internal Flag to signal the shell that it is running inside a docker stack belonging to the distillery"`
+}