[Pulp-list] New Services API handler

[Pradeep Kilambi]

FYI,

While working on dependency resolution story, I had the need to be able to pass in multiple pkg and repo objects in POST which made it hard/awkward to perform on existing /packages/%s/<action> handler. So after discussing briefly with jconnor we decided that its better to have a separate handler for one off operations such as this. So I defined a new top level collection called 'services'. We can renamed this to something else if people like. 

With this new model, the rest calls will hit '/services/<operation>/',

dependencies : '/services/dependencies/'
search       : '/services/search/'

This handler can now be used as a place holder for operations that dont make sense or makes it hard on existing collections.

Thanks,
~ Prad