Remove the need for net.worker_restart()

[steve-chavez]

Problem

Currently to change the configs such as pg_net.ttl/pg_net.batch_size we need to restart the worker. This generates a failure plus some unnecessary log lines.

Solution

With shared memory, plus a GucStringAssignHook we don't need to restart the worker. Once a user does SET pg_net.batch_size this should change the config on the next worker iteration.

[riderx]

i think i supabase cloud we cannot even call net.worker_restart() so we need to restart the db

[steve-chavez]

Note that that should be solved from v0.12, net.worker_restart is not a security definer function anymore.

[steve-chavez]

ALTER SYSTEM is a problem for pipeline mode as mentioned on #160 (comment)