Initial spike

This is mostly to solidify the overall structure with the agent,
plugins, and testing philosphy.

plugins/registry.go

@@ -0,0 +1,15 @@
+package plugins
+
+import "github.com/vektra/cypress"
+
+type Plugin interface {
+	Read() ([]*cypress.Message, error)
+}
+
+type Creator func() Plugin
+
+var Plugins = map[string]Creator{}
+
+func Add(name string, creator Creator) {
+	Plugins[name] = creator
+}