First split into crockery init and crockery run

The init command creates a crockery.db file containing the domain name and
TLS keypair. The run command starts IMAP and SMTP services based on that file.

Supporting only a single domain is starting to look a bit unnecessary. We'll
see how that goes.

vendor/github.com/asdine/storm/index/options.go

@@ -0,0 +1,15 @@
+package index
+
+// NewOptions creates initialized Options
+func NewOptions() *Options {
+	return &Options{
+		Limit: -1,
+	}
+}
+
+// Options are used to customize queries
+type Options struct {
+	Limit   int
+	Skip    int
+	Reverse bool
+}