Directory and naming cleanup in next major release

[frangio]

It would be nice to do some cleanup in the next major release.

Here's my personal wishlist. Everything is open to discussion.

• Move Pausable from lifecycle into utils. There is only one contract in lifecycle and I'm not sure that we'd want to add any other contracts under that category.
• Remove drafts directory. It didn't work the way we wanted it to. Either graduate stuff to be properly supported, or create feature branches (but we should work on them to finish them proper!).
• Rename Secondary into something else. It's a really bad name.

[nventuro]

Fixed via #2120 and #2122.