routing: split data onto many files

[pronebird]

macos/data.rs is over 1000 LOC long. This PR aims to split data.rs onto multiple smaller files under macos/data which should be easier to maintain in the long term.

Since this looks like huge change, I'd suggest you to pull the branch and run:

git -c color.diff.newMoved=black -c color.diff.oldMoved=black diff --color-moved=plain --unified=0 head~1

which should show you the same code in black and then what was added/replaced/removed in green and red.

Please run and test these changes of course to make sure that I didn't break anything.

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This change is 

[pronebird]

On a side note, wanted to ask about the use of futures crate in routing. Is it some ancient relic that perhaps should be replaced with tokio which seems to be uber popular and almost ubiquitous these days?