Previously we would unconditionally add Cargo.toml to the fileset. We
mostly use buildRustCrate in tvix so it does not make sense to add it by
default, instead I made it so you enable cargoSupport if you want
Cargo.{toml,lock} to be added to the fileset.
Change-Id: I5a6016534fc5599e85ab581fe3d9b81e7a24f940
Reviewed-on: https://cl.tvl.fyi/c/depot/+/11950
Reviewed-by: flokli <flokli@flokli.de>
Tested-by: BuildkiteCI
Autosubmit: Ilan Joselevich <personal@ilanjoselevich.com>
63654fbeb1