Added apache service. TODO: paramatrize it.
Added apache template.

templates/monitors/apache.j2:
- Rules are loaded from monit_apache_rules variable if present;
- Groups are loaded from monit_apache_groups variable if present.

defaults/main.yml:
- added default values for apache template.
Added a description for apache variables.
Merge pull request #4 from mtpereira/apache

Apache