Add cron description to Frequency column in the Connections list.

[ilyaberd]

When schedule is set to cron, it will be great to add cron description to the list of the connections.
It is the same description available in in the settings, under cron expression.
For example for cron expression: 0 0 11,23 * * ?
Value in the frequency column will be:
Cron (at 11 and 23 hours)