Re-Export apis like we do models

[rtaycher]

Is your feature request related to a problem? Please describe.

Sometimes there are a lot of apis to import to even do a simple thing

Describe the solution you'd like

Models are re-exported, allowing us to

import my-openapi-lib.models as m
from my-openapi-lib.api.do_the_things import create_thing_to_do
create_thing_to_do.sync(client=c, json_body=m.ThingModel(...))

# I'd like to be able to do
from my-openapi-lib import api
api.do_the_things.create_thing_to_do.sync(client=c, json_body=m.ThingModel(...))
# and
from my-openapi-lib.api import do_the_things
do_the_things.create_thing_to_do.sync(client=c, json_body=m.ThingModel(...))