re-enable split-debuginfo

[kamirr]

Acceptance Criteria:

• Bump rust to 1.70
• fix TODO in Cargo.toml, i.e. revert the change applied in this patch.

Why
split-debuginfo may decrease compilation time and greatly reduces the size of emited binaries build in debug mode. debug-mode yagna is 1.7GiB by default, but only 114MiB without embedded debug data. This was disabled due to a bug in cargo which is fixed since version 1.69.

Note: split-debuginfo only works on mac OS (and Windows?)

Blocked by:

• Add split-debuginfo print option rust-lang/rust#104104
• Fix split-debuginfo support detection rust-lang/cargo#11347
• Bump Rust to 1.68 #2438