Noted by rajeshwar.shanigarapu@moodle.com while testing MDLQA-18449 during the 4.4 QA cycle.

The database availability settings are confusing and it needs to be reviewed and improved.

Firstly, they are not well documented so it's hard to know if the "Read only from" and "Read only to" works with the "Available from" and "Available to" dates and if those dates need to be within the date period the activity is available to students.

Furthermore, there are no help buttons like assignment activity and also the form validation for those fields only does the basic check to verify the end dates are not before the start dates.

This improvement is about review those settings, improve the UI adding help buttons and stricter validation, add Behat coverage and document it properly.