Changes the default fetcher in the Rust Platform to be the newer
`fetchCargoTarball`, and changes every application using the current default to
instead opt out.
This commit does not change any hashes or cause any rebuilds. Once integrated,
we will start deleting the opt-outs and recomputing hashes.
See #79975 for details.
Unfortunately, buildRustPackage isn't very flexible right now, and most
of these attrs can't be overridden. This is needed for some general
patch work, but isn't really long term sustainable. I plan on reverting
this after Vector 0.6 is out.
Signed-off-by: Austin Seipp <aseipp@pobox.com>
