Feature request: `commitizen` should support revert commits

I know that a similar request was discussed before, however angular does contemplate revert commits.

As a minimum, cz check should accept commit messages beginning with revert:, otherwise when it is configured as a pre-commit hook it does not allow revert commits.

Moreover, IMHO a cz revert command should be added, accepting the <commit> to revert. It should run git revert <commit>, including in the message body: This reverts commit <hash>. as per angular instructions. See information on git revert.

For examples of revert commit messages, see for instance standard-version and conventional-changelog commit logs.

Notice that both commitlint and gitlint support revert commits.