Add a top level folder for Aspire cli archives on linux

### What needs to be done

1. Aspire cli is packaged in archives for multiple OSes (`eng/clipack/*.csproj`). The binaries are in the root directory for all the archives. For the `linux` variants put the binary in a top level directory called `aspire`. Don't do this for others.

2. Adjust the scripts that download these archives namely `eng/scripts/get-aspire-cli.sh` and `eng/scripts/get-aspire-cli.ps1` to handle this special case.

### Other useful information

- The build can be tested by running the build script with `/p:SkipManagedBuild=true`. And this would result in all the archives like `aspire-cli-osx-arm64*`.

### Validating

- Check the generated archive to ensure the binary is in a top-level folder on linux. But is in the root for others.
- Ask for the azure internal pipeline to be run, to validate whether this works. And iterate with the user till this is producing the correct results. You cannot run this directly.

- Ensure that the download scripts correctly install the `aspire` binary in to the install folder on linux (eg. `~/.aspire/bin`).