Consider adding a root directly to dotnet archives

We recently heard feedback that dotnet archive packages (.zip, .tar.gz) should include a root directory. A quick survey of archives from other platforms suggests that our pattern is unique.

Here's an example:

```bash
rich@lussier:~$ curl -O https://static.rust-lang.org/dist/rust-1.86.0-x86_64-unknown-linux-gnu.tar.gz
% Total % Received % Xferd Average Speed Time Time Time Current
Dload Upload Total Spent Left Speed
100 334M 100 334M 0 0 94.0M 0 0:00:03 0:00:03 --:--:-- 94.0M
rich@lussier:~$ tar -xf rust-1.86.0-x86_64-unknown-linux-gnu.tar.gz
rich@lussier:~$ ls rust-1.86.0-x86_64-unknown-linux-gnu
COPYRIGHT clippy-preview llvm-tools-preview rust-installer-version
LICENSE-APACHE components rls-preview rust-std-x86_64-unknown-linux-gnu
LICENSE-MIT git-commit-hash rust-analysis-x86_64-unknown-linux-gnu rustc
README.md git-commit-info rust-analyzer-preview rustfmt-preview
builder-config install.sh rust-docs version
cargo llvm-bitcode-linker-preview rust-docs-json-preview
```

The instructions from our website require a significantly more complicated model.


We should consider this change for .NET 11.