Respond to not-configured channels by default

[pkosiec]

Overview

After a conversation on the community Slack with Ben Mathews (link) and further investigation of the reported issue on a call, we found out that the issue consisted of a few factors, including a counter-intuitive default Botkube behavior.

Acceptance Criteria

Bring the following improvements:

• Add an option (on by default) to respond to any channel. It could be turned off for multi-cluster scenarios
• The default values.yaml only shows the "default" channel. Provide some additional (commented out) examples to demonstrate how a user might want to configure other channels
• command move guard → too many info logs and warnings → move them to debug
• Update docs

Reason

Improve user experience for new users.