breaking: refactor from service-based advertising to prefixed-based

[encodeous]

This PR makes a major change in the way nylon advertises routes.

Previously, we advertise based on named "services", but in this PR, we move to a more general prefix-based approach.

Other changes:

• We also give the user options to include/exclude prefixes (previously difficult)
• Allow the definition of pre_up, pre_down, post_up, post_down commands
• Allow the definition of multiple addresses
• Removed the behaviour of automatically configuring aliases on the TUN interface for all services
• (as this already is a breaking change to the config) updated the config to have better format (Snake case instead of... just lowercase words)