Improve documentation for consumer chain relaying

[ancazamfir]

Summary

For successful relaying on consumer chains hermes needs to be explicitly configured with ccv_consumer_chain = true. This is described in the config file but I think it deserves a dedicated section as for ICA for example:
https://hermes.informal.systems/documentation/configuration/configure-hermes.html#support-for-interchain-accounts

Problem Definition

So far almost all operators ran into misconfiguration issue for consumer chains.

Acceptance Criteria

Clear documentation for ICS

• Add a section to the "Configuration" section talking about the ccv_consumer_chain option
• Add a section to the "Troubleshooting" section on errors that might occur when the
  ccv_consumer_chain flag is not set when attempting to relay for a consumer chain

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