Remove `owning_ref` to avoid (unused) unsoundness

[kevinaboos]

See: Kimundi/owning-ref-rs#78

We don't currently use the unsound functions, but it's a good idea to patch this nonetheless (in the root Cargo.toml's [patch] section).

[kevinaboos]

Could also consider replacing owning_ref with https://crates.io/crates/reffers

[kevinaboos]

I think we'll need to replace owning_ref entirely. Good candidates are:

• self_cell: good but a bit limited
• ouroboros: huge and perhaps too much build-time overhead
• reffers: not as well-tested as others

[kevinaboos]

Note that all other RustSec advisory database warnings have been addressed. owning_ref is all that remains

[kevinaboos]

As an alternative and better solution, we no longer support using owning_ref anywhere in Theseus. All of the crates that use it have now been removed; all that's left is to remove it from various lock implementations that offer compatibility with it by implementing stable_deref_trait (e.g., MutexIrqSafe, MutexSleep and similar).