Fix CLI flag naming

[hariso]

Description

Fixes #2062.

There were two issues:

1. With boolean flags, e.g. api.enabled, the "issue" was in the usage. Sometimes we use --api.enabled true, but pflag doesn't like that (link, pflag is used by Viper that our CLI uses)
2. With other flags, the issue was with naming. When unmarshalling the input map (that contains flag names and values) into Conduit's configuration structs, certain fields were skipped because of name mismatches. mapstructure, used by viper, assumes default key names for Go struct fields, but we were using non-default in certain cases.

As part of above changes, http.address and grpc.address were renamed to api.http.address and api.grpc.address respectively.

Quick checks

• I have followed the Code Guidelines.
• There is no other pull request for the same update/change.
• I have written unit tests.
• I have made sure that the PR is of reasonable size and can be easily reviewed.

[raulb]

Thank you @hariso !!