Use Middleware instead of Decorator for nomenclature

[odeke-em]

Currently we are using Decorator for wrapped functions that take in a context, multistore and then invoke next. The usage of the term Decorator required some developer education on Python and the idea of wrapping functions to produce other functions.
In the meeting @jaekwon raised the familiarity to Node.js' Express framework, but in Express they call them Middleware and in Express, Middleware take in a (request, response, next Handler) where the usage is similar to what Decorate does.

This is a suggestion for us to change names from Decorator to Middleware.
I believe Middleware is more familiar to people and easier to look up as Go's networking libraries also talk about Middleware and it's a popular concept in web services development too.

[ebuchman]

Agreed, but the concept of decorators has now been removed altogether