Feature Description:

We now feature multiple remote connection providers in our codebase (Dev-Containers, WSL, SSH). While WSL and Dev-Containers have their own package, SSH is still provided via the base @theia/remote package. However, since both WSL and Dev-Containers uses @theia/remote as a dependency, it's not possible to provide either features without also providing SSH support.

To fix this and to separate concerns in the theia packages, we should split off the SSH support into a @theia/remote-ssh package.