Add support for access logging

There isn't currently a standard technique for enabling a Jenkins access log across the various installation methods that this cookbook supports:
* rpm packages do support a setting JENKINS_ENABLE_ACCESS_LOG, however the path and file name are hardcoded
* Debian packages are missing any support per [JENKINS-18870](https://issues.jenkins-ci.org/browse/JENKINS-18870)
* war installation provides no access log support

This pull request adds two new attributes that provision a standardized access logging capability across the above installation methods:
* node['jenkins']['master']['access_log'] - the filename of the access log
* node['jenkins']['master']['access_log_enabled'] - whether to provision access logging or not

See also https://wiki.jenkins-ci.org/display/JENKINS/Access+Logging