Connect backend refactor (#801)

* Move connect backend code to its own package
* Move errors into the connect package
* Add NewBackend func

pkg/connect/types.go

@@ -0,0 +1,20 @@
+package connect
+
+import "errors"
+
+var (
+	errBackendConnectError = errors.New("unable to connect to the auth backend")
+	errConnStringRequired  = errors.New("connection string is required")
+)
+
+// Request holds the resource request details
+type Request struct {
+	Resource string            `json:"resource"`
+	Token    string            `json:"token"`
+	Headers  map[string]string `json:"headers,omitempty"`
+}
+
+// Credential holds the database connection string
+type Credential struct {
+	DatabaseURL string `json:"database_url"`
+}