builds.sr.ht: Allow worker settle timeout to be configured 24 days ago

From Jakob Meier to ~sircmpwn/sr.ht-discuss

I've set up my personal sourcehut instance with build.sr.ht.
However, my sourcehut builds kept failing (they won't even start):
 > [#14] 2023/11/04 19:10:53 Booting image alpine/edge (default) on 
port 22113
 > [#14] 2023/11/04 19:10:53 Waiting for guest to settle
 > [#14] 2023/11/04 19:12:53 Error: Settle timed out after 3 attempts

After looking at the worker source code,
I noticed that the settle timeout is hard-coded to 120 seconds [1].
Because it is hard-coded, I had to rebuild the worker and replace the
binary to change it (5 minutes did the trick, because it takes about 2 
1/2
minutes to spin up).
 > [#16] 2023/11/05 09:28:23 Booting image alpine/edge (default) on