ccvTimeoutTimestamp should be included in consumer addition proposal

[shaspitz]

Problem

This PR #376 enables the provider and the consumers to have different CCV timeout periods. This could have negative implications on security, if a consumer chain is able to make this timeout parameter dangerously small. Note that a consumer could have changed this hardcoded parameter before #376

We should better expose this parameter to provider validators when a consumer chain is being spawned, and perhaps include the parameter in the consumer addition proposal. We should also not allow this parameter to be changed through consumer governance.

Closing criteria

Fix the issues described above

[jtremback]

As we discussed today, this should probably just go in the regular consumer param section and defaults. The genesis.json for a new consumer needs to be checked carefully.