Update `nslsii` to use `pyproject.toml`

[mrakitin]

We should use https://github.com/scientific-python/cookie (we use it already for hextools, srx-caproto-iocs, etc.).

Add a [sync-experiment] install candidate, so we can do pip install .[sync-experiment] instead of having to track dependencies in multiple places.

(lifted from https://github.com/NSLS2/ansible/pull/2325#issuecomment-2447750489)