Split out dev requirements into smaller sets for faster loading by automation scripts

[mhucka]

What is the task?

In particular in CI jobs, loading dev-requirements.txt is time consuming compared to other tasks. We should split out requirements for different purposes (linting, formatting, etc.) so that automation can run faster.

(Optional) Do you have ideas or preferences for the approach?

Cirq uses this approach. We could borrow ideas from Cirq's dev_tools/conf approach.

How urgent is this for you?

P2 – needed within two quarters