Provide an option to get only a part of Botkube configuration

[mszostok]

Overview

We should allow getting only a part of Botkube configuration. We have at least two options:
-@Botkube config {name}

• @Botkube config - returns configuration but in a context of a given channel.
• @Botkube config --all - returns the whole (even data that is not connected with a given channel) Botkube configuration.
• @Botkube config executors - returns executors configuration in a context of a given channel
• @Botkube config actions -returns actions configuration in a context of a given channel
• etc.
• or supporting a more generic approach like @Botkube config --json-path={property_name} e.g. --json-path=communicators.slack (similar to what kubectl does)

Acceptance Criteria

• provide an option to get only a part of Botkube configuration.
• provide an option to get configuration in a context of a given channel (e..g. get configuration of all enabled executors in a given channel).