Configurable binary location on the remote side

[Riebart]

Currently it's hardcoded to invoke the default location of the wolfram binary on a Raspberry Pi, but this could easily be promoted to an argument.

[Riebart]

Raspbian just got bumped to 11.3, so this breaks the script.

• Auto-detection based on remote-type would also be handy, so something like:
  • RemoteBinary explicitly set the remote binary location, supports Automatic when RemotePlatform is set
  • RemotePlatform Set the remote platform, valid options are those in SSHKernel`SupportedPlatforms.