remove workspace hack from libs (#8780)

This removes workspace hack from all libs, not from any binaries. This
does not change the behaviour of the hack.

Running
```
cargo clean
cargo build --release --bin proxy
```

Before this change took 5m16s. After this change took 3m3s. This is
because this allows the build to be parallelisable much more.

libs/remote_storage/Cargo.toml

@@ -32,7 +32,7 @@ scopeguard.workspace = true
 metrics.workspace = true
 utils.workspace = true
 pin-project-lite.workspace = true
-workspace_hack.workspace = true
+
 azure_core.workspace = true
 azure_identity.workspace = true
 azure_storage.workspace = true
@@ -46,3 +46,4 @@ sync_wrapper = { workspace = true, features = ["futures"] }
 camino-tempfile.workspace = true
 test-context.workspace = true
 rand.workspace = true
+tokio = { workspace = true, features = ["test-util"] }