add consumer key helpers

[yadutaf]

And here is the python version of ovh/go-ovh#3. It follows the same design with 3 simple helpers and HTTP Verbs list "constants".

A simple code excerpt being worth a 1000 lines of text, here it is:

# Common authorization patterns
API_READ_ONLY       = ["GET"]
API_READ_WRITE      = ["GET", "POST", "PUT", "DELETE"]
API_READ_WRITE_SAFE = ["GET", "POST", "PUT"]

# Helpers
class ConsumerKeyRequest(object):
    def add_rule(self, method, path): pass
    def add_rules(self, methods, path): pass
    def add_recursives_rules(self, methods, path): pass

ping @rbeuque74 @VincentCasse @gregdel @PouuleT @LukeMarlin

[VincentCasse]

LGTM