Feature: Allow to configure fixity cronjob from ansible-archivematica-src role

[mamedin]

Please describe the problem you'd like to be solved

Ansible archivematica role doesn't allow to define cronjob time scheduling or disable the job from ansible variables

Describe the solution you'd like to see implemented

Add new variables in the ansible role to define time variables and to allow disabling cronjob.

Describe alternatives you've considered

Additional context

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