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.
pyo3-pack has been renamed to maturin version 0.7.0. Other larger
changes are:
- Mixed rust/python layout
- Added PEP 517 support
- Support settings all applicable fields from the python core
metadata specification in Cargo.toml