[Umbrella] Dynamic API configuration

[kgriffs]

1. Have a way to add additional middleware outside the API initializer.
2. Provide a way to remove middleware.
3. Provide a way to remove routes.

[kgriffs]

Prior art/experiments re (1):

• https://gitlab.com/skosh/falcon-helpers/blob/master/falcon_helpers/middlewares/multi.py
• https://gitlab.com/skosh/falcon-helpers/blob/master/falcon_helpers/app.py#L35

[myusko]

@kgriffs Hm, not bad proposals, with the first two, I totally agree, it will be helpful to add middleware outside the API initializer, but for the third one, I don't see any use case:) IMHO.

Anyway, I'll play with it.