Remove `config` dependency from `discovery`

[shubheksha]

This is a follow-up to #3013. In #3629, we removed config dependency from the discovery package partially. We need to decouple these packages completely.

[shubheksha]

@krasi-georgiev, I believe you're working on something along these lines?

[krasi-georgiev]

yep , here is the first draft , but it is a WIP
#3605

[krasi-georgiev]

I was thinking of a global Config manager which is responsible for loading/parsing/providing the configs (thorugh Read() struct{.....} interface)

Each package will use the Read interface and converts the input to the package internal config types so neither the config nor any other packages have to import shared structs types.

[shubheksha]

Sounds good! /cc @juliusv