Update configure_me to 0.4

[Kixunil]

The new version bumps toml to 0.5, which enables de-duplicating toml crate - there are currently two versions 0.5 and 0.4. There's no significant breakage apart from disabling certain invalid configurations that are almost certainly irrelevant to lnp-node.

I could submit a PR but I'm low on time right now.

OT: I do have your feature request in the back of my mind, unfortunately, I have shitton of other work to do lately.