[PATCH v4 4/7] gc: add gc.bigPackThreshold config

The --keep-largest-pack option is not very convenient to use because you need to tell gc to do this explicitly (and probably on just a few large repos). Add a config key that enables this mode when packs larger than a limit are found. Note that there's a slight behavior difference compared to

[PATCH v4 4/7] gc: add gc.bigPackThreshold config

The --keep-largest-pack option is not very convenient to use because you need to tell gc to do this explicitly (and probably on just a few large repos). Add a config key that enables this mode when packs larger than a limit are found. Note that there's a slight behavior difference compared to