Collect streaming request bodies (#23)

Fixes #22.

Request bodies of a certain size come in streaming and the properties
return `nil`. We should check this and perform a check similar to what
Vapor's routing tools do internally:

https://github.com/vapor/vapor/blob/1d53c99b6ede0131bb02305f0d62fb2c6c830f3b/Sources/Vapor/Routing/RoutesBuilder+Method.swift#L152

Support ordered dictionaries from URL Routing 0.4.0 (#20)

Make middleware public (#10)

🌱

Co-authored-by: Stephen Celis <[email protected]>