Add container leve securityContext and missing probes

[michalschott]

Currently it is unable to set for example readOnlyRootFilesystem in security context as this is set per container basis.
Probes for access-logs container are not defined.

This PR fixes above problems.

[jcmoraisjr]

Hi thanks for the improvements! Sorry about taking so long to answer. Some suggestions below:

• what about add a distinct securityContext under controller.haproxy and use it in the haproxy container?
• please add also the new entries in the readme file.

[michalschott]

@jcmoraisjr pushed an update with your suggestions.

[jcmoraisjr]

Lgtm thanks! Merging.