alter asyncio loop syntax

[ddkohler]

Using newer syntax for asyncio looping (i.e. avoid using get_event_loop), fixing the issue where our signal handlers were not finishing execution in python >=3.12.

DO NOT MERGE. Lots of testing should be done before merging.

• asyncio framework avoids get_event_loop
• servers are contained in a set instead of a list (probably unnecessary)
• resolves python >= 3.12 (ubuntu-latest): non-graceful shutdown #84
• addresses Prepare for Python 3.14 changes #83

Tasks

• test on lab instruments
• investigate python 3.12 yields huge memory accumulation for yaq daemons #79 effects for expediency postpone this investigation
• changelog

[untzag]

https://docs.python.org/3/whatsnew/3.14.html#id10

(trying to understand this, found this documentation helpful)

[untzag]

Thank you so much @ddkohler, sorry it took so long to merge this very important work!