[security] No need to log a merged config.

[Zensey]

IMHO there's no need to log a merged config.
It can rise a security problem due to exposure of a sensible data, like passwords / addresses.

This issue can be addressed by :

• not logging merged config it at all
• introduction of a new tag for sencible info and then check it and masking sensible data before loging

[smgladkovskiy]

Show more info while reading and merging configs for more control without dump all.

@Zensey what do you think about it?