CBQE-0: move monster generated json-generator to tuq generator and changed end parameter to docs_per_day

Two Changes
1) We moved this to tuq_generators. Also, its format is what we use in testrunner for loading.

USAGE
x =  JsonGenerator()
list = x.generate_docs_using_monster(
    "go run ~/gocode/src/github.com/prataprc/monster/monster/monster.go ",
        key_prefix=  "key",
            pod_name = "projects.prod", num_items = 10, seed = 1)

print list

2) Changed end parameter to docs_per_day for other json generators


Change-Id: I3921a37dd36c49bdaa7fb2a26317d10afd4a6182
Reviewed-on: http://review.couchbase.org/43937
Tested-by: buildbot <build@couchbase.com>
Reviewed-by: Parag Agarwal <agarwal.parag@gmail.com>
Tested-by: Parag Agarwal <agarwal.parag@gmail.com>