Development Guidelines for middlewares

Best practices:

Do not use panic in middleware creator functions in case of invalid configuration.
In case of an error in middleware function handling request avoid using c.Error() and returning no error instead because previous middlewares up in call chain could have logic for dealing with returned errors.
Create middleware configuration structs that implement MiddlewareConfigurator interface so can decide if they want to create middleware with panics or with returning errors on configuration errors.
When adding echo.Context to function type or fields make it first parameter so all functions with Context looks same.