Promote bcfg2-info to have it's own Options dict

Turns out that CLIENT_COMMON_OPTIONS and SERVER_COMMON_OPTIONS
conflict.  Adding ppath and max_copies (turns out the latter is also
necessary) to the bcfg2-info code directly seemed like a maintenance
problem waiting to happen, so I factored that out into a new
INFO_COMMON_OPTIONS dict.  That will keep any options parsing special
cases out of the bcfg2-info code hopefully be more maintainable
going forward.