folly::fibers::Baton API consistency with folly::Baton

folly::fibers::Baton API consistency with folly::Baton

Summary:
[Folly] `folly::fibers::Baton` API consistency with `folly::Baton`.

Specifically, the suite of `wait`, `try_wait`, `try_wait_for`, and `try_wait_until` members and member templates.

Hold onto the `timed_wait` members for now, but mark them deprecated.

Additionally, for consistency, offer main-context function params consistently for all `try_wait_for`, `try_wait_until`, and both variants of `timed_wait`.

Reviewed By: andriigrynenko

Differential Revision: D6531145

fbshipit-source-id: 960fba48716b12b0ef53262786eacab88d8b2375