Added ability to change legate options through LocalPreferences.toml

[ejmeitz]

Can now define a LocalPrefernces.toml which contains the legate command line args. This file is parsed in __init__ and pased to legate::start.

Example LocalPreferences.toml (should be in same directory as Project.toml). You need the use_local_prefs cause for some reason there's no way built in Preferences.jl to check if someone defined a LocalPrefernces.toml or we can just check manually I suppose.

[cuNumeric]
use_local_prefs = true
cpus = 10
gpus = 1

If there is no LocalPrefernces.toml the arguments passed when julia was called are passed to legate.

TODO

• @krasow since your get_machine_info actually works, please try setting this and seeing if it changes what that prints out
• check if you can dynamically change these (via some function) and restart legate with the new settings.
• change CI to 1 CPU and 0 GPU, maybe that will fix it

[krasow]

Even with a custom LocalPreferences, I am unable to change the output of cuNumeric.get_machine_info(). We are assuming that we can pass the same arguments from https://docs.nvidia.com/legate/latest/usage.html to legate::start(argc, argv) and cupynumeric::initialize(argc, argv). This assumption is confirmed here: https://github.com/nv-legate/cupynumeric/blob/5371ab3ead17c295ef05b51e2c424f62213ffd52/examples/cpp/stencil/stencil.cc#L82