Reduce or remove usage of fuses in favor of dropping JulietClient

[RitaMAllenCA]

The Juliet RPC-level clients come with built-in facilities to shut down connections, without having to rely on watch a fuse to be notified of shutdowns. By leveraging these the code can be greatly simplified.

[marc-casperlabs]

This has been superceded by the conman implementation, which uses something similar.