Bring more structure to RU-specific code as a preparatory step for multiRU support:

• move RU-specific files under ru/<RU-type>/ . This mostly moves Lopcomm programs and configuration files there.
• move RU-specific instance code there as well. This also mostly moves Lopcomm specific services and promises there.
• bring more structure in naming. As buildout has global namespace use ru_<RU-type>_ prefix to avoid collision in names.

This should be a preparatory patch with practically no semantic change, but preparing ground for further multiRU landing.

/cc @jhuge, @lu.xu, @xavier_thompson, @Daetalus