Refactor plugins configuration

[damyan]

Summary

Currently, each plugin (except metal) is configured through a string list of parameters. It is a limitation coming from coredhcp. With the configuration becoming more and more complicated, a dedicated knowledge about parameter order and meaning is required. Better would be a configuration through a plugin-specific yaml file (as for the metal plugin), where the parameter meaning can be deduced from the configuration structure.

Basic example

IPAM configuration, old:

- plugins
  - ipam: ipam-ns ipam-subnet1,ipam-subnet2
[…]

IPAM configuration, new:

- plugins
  - ipam: ipam_config.yaml

ipam_config.yaml:

namespace: ipam-ns
subnets:
  - ipam-subnet1
  - ipam-subnet2

Motivation

This wil improve greatly the configuration readability.

Implement for:

• blufield
• httpboot
• ipam
• metal
• onmetal
• oob
• pxeboot

[damyan]

/cc @afritzler