Initial bootrap of application

- Creates scaffold for router and server
- Main program set up for environment, OS signal listener
- Makefile generic commands

internal/http/errors.go

@@ -0,0 +1,8 @@
+package http
+
+import "errors"
+
+var (
+	ErrUnknownError     = errors.New("unknown error occurred")
+	ErrUnrecognizedCode = errors.New("unrecognized status code")
+)