GUI: Add server startup timeout setting & build process tweaks

[SunderB]

Hopefully this’ll help make errors easier to debug in startup issues like #2393 etc.

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This is a copy of #2406 but updated to be applied to the new main branch.

[SunderB]

The option seems to appear as it should on my system :) (I've not been able to test if the setting affects the timeout though) I don't know if that location is the best for that option, I've just put it there for now. If it would fit better elsewhere then it can be changed :)

[SunderB]

It seemed possibly to work? I set the setting to 120 and temporarily changed a line of code to always do the full timeout, and 120 dots appeared in the log:

[GUI] - UDP OSC Server ready and listening
...
[GUI] - Sonic Pi Server successfully booted.
[GUI] - waiting for Sonic Pi Server to respond...
........................................................................................................................
[GUI] - Sonic Pi Server connection established
[GUI] - honour prefs
[GUI] - asking OSC server to start
[GUI] - cue port in internal mode

[SunderB]

Closing this for now since it doesn't seem like this is needed right now, and nothing has happened with it for a while.