Add documentation on the new crontab configuration for Docker.
Review Request #2235 — Created Sept. 23, 2021 and updated
This adds docs on how to use the crontab support added to Docker in
4.0.4. There's a new section showing how this can be used, and a
reference in the configuration options.
Built the docs. Checked for build errors, spelling errors, and bad links.
Reviewed at https://reviews.reviewboard.org/r/11756/