[WIP] Add new build options for setup.py

[pganssle]

Fixes #597.

This will add the --no-zoneinfo, --tzfiles and --tzpath command line arguments so that downstream distributors can easily build versions of this where they are better able to manage how zoneinfo files are distributed.

To do:

• Add better fallback message for when zoneinfo tarball is not distributed.
• Add tests
• Add documentation
• Possibly forbid these options in things like sdist?
• Test to see if this can be made to work with pip

CC: @wagner-certat @agx @ericvw @jelly @hguemar

Thoughts from downstream distributors about how much this would help? Would something else be preferable?

The whole thing is a bit of a monstrous hack, unfortunately, but I think it's slightly preferable to everyone patching themselves.

[ghost]

Please add an entry to the NEWS file about this new possibility for packagers (so they notice it without digging in the code).

[pganssle]

@wagner-certat The current release procedure doesn't generate the NEWS file until the release is prepared, though I would like to change that with #592.

That said, "add documentation" is one of the bullet points.