Improved fail2ban setup by switching to a template instead of using lineinfile/ini_file

lineinfile doesn't work for the cases that have multiple matches (e.g., 'action'), because ansible only lets you replace the last one, and the DEFAULT one is always the first in such cases.

ini_file doesn't work for updating the action, because ansible doesn't provide a way of using a raw config parser, and the default jail.conf includes '%(__name__)...' in some of the action_ values, which causes an interpolation error when tryig to set action to something like '%(action_mwl)s'