Support custom timeout_commit in testing mode

[cmwaters]

Summary

Since v3, timeout commits are now dictated by the application. This has made it difficult in the case of testing, where we and others want to be able to have short timeouts. Both sovereign and eiger have reported this being problematic for them.

Proposal

Introduce either an environment variable or a flag to force set the timeout commit. We may want to consider this to also set the square size as well. If we're concerned about misuse on a live network we can add chainID checks.

[cmwaters]

Furthermore, we might want to, if it's not too breaking, to rename the current timeout_commit and timeout_propose in the config.toml (or at least the go struct) to something else so as to avoid confusion. Most teams may still be setting these values and think it will change the times

[rootulp]

Introduce either an environment variable or a flag to force set the timeout commit. We may want to consider this to also set the square size as well.

We have the OVERRIDE_MAX_SQUARE_SIZE env variable which can override the max square size at binary build time so we could add another for overriding timeout_commit.

Alternatively, we could override the timeout_commit when the chain_id is test similar to how we override the upgrade height delay to 3 here.

Furthermore, we might want to, if it's not too breaking, to rename the current timeout_commit and timeout_propose in the config.toml (or at least the go struct) to something else so as to avoid confusion. Most teams may still be setting these values and think it will change the times

IMO we should deprecate the config timeout_commit and timeout_propose in v3.x.x and remove them in v4.x.x.

[rootulp]

Related: #4023