[cluster-test] [ci] Decouple --run-ci-suite and --changelog
[cluster-test] [ci] Decouple --run-ci-suite and --changelog

This allow to combine `--changelog` and `--run-ci-suite` flags.
This is needed because when cluster test runs from CI, it can't reliably get from-to commits for changelog

For CI run we will need to specify them manually:
```
ct --run-ci-suite --changelog commit_from commit_to
```

Closes: #1908
Approved by: sausagee

aptos-labs/aptos-core,libra/libra,aptos-labs/aptos-core,aptos-labs/aptos-core,aptos-labs/aptos-core,aptos-labs/aptos-core,aptos-labs/aptos-core,libra/libra,libra/libra,libra/libra,libra/libra,aptos-labs/aptos-core