[Packaging] Add a log subcommand to crossbow to get the build logs of tasks

For people who don't want to have to click on things (myself included), a `crossbow` subcommand that allows task log tailing would be most welcome.

**Reporter**: [Phillip Cloud](https://issues.apache.org/jira/browse/ARROW-2933) / @cpcloud

_{**Note**: *This issue was originally created as [ARROW-2933](https://issues.apache.org/jira/browse/ARROW-2933). Please see the [migration documentation](https://github.com/apache/arrow/issues/14542) for further details.*}