Allow disabling settings catalog

When initializing Puppet as a library to handle master requests I do not want the settings catalog applied every time. There should be a setting that I can set when initializing Puppet that disables setting catalog compilation and application.

• Are there packaging changes needed in FOSS if we do this? For example, we use the settings catalog to manage permissions on the codedir, which packaging creates as root.

This ticket tracks adding the ability to prevent the settings catalog from being applied, while SERVER-2240 tracks puppetserver opting in to that behavior.