restruct config initialization

[dai1975]

change config initialization structure to use logger in chain and/or prover init

before:

 PersistentPreRunE
 +-- InitConfig
 |   +-- UnmarshalJSON
 |   |   +-- json.Unmarshal
 |   |   +-- config.Chains[].Init
 |   |   +-- config.chains = config.Chains[].Build
 |   +-- InitChains
 |      +-- config.chains[].Init
 +-- initLogger

after:

 PersistentPreRunE
 +-- UnmarshalConfig
 |   +-- json.Unmarshal
 +-- initLogger
 +-- InitConfig
 |   +-- config.Chains[].Init
 |   +-- config.chains = config.Chains[].Build
 |   +-- initChains
 |      +-- config.chains[].Init

[dai1975]

This function called by only this file.

[dai1975]

Old function signature (c *Config) InitConfig(ctx *Context, ...) is a bit confusing that c and ctx.Config should be same pointer or not.

[siburu]

@dai1975 Great work overall, thank you! I've left some comments in the code. Could you please review them and make the necessary changes?

[siburu]

@dai1975 LGTM. Thank you!!