Revert "EDUCATOR-2231 Drop the enrollment start and end date fields from publisher course runs model"

This reverts commit d5a6bea1.

When publishing, we want to give ecommerce the UUID of the course
so that it doesn't have to turn around and ask us for that same bit
of information.

This reverts commit e4eaf0d5.

LEARNER-3770

When publishing a course run to ecommerce and discovery, also push
any entitlements for its course to those same services.

This reverts commit 3db5a5ef which was
itself a reversion to back out these changes while we fixed our staging
services.

LEARNER-4031

When creating a course run in the Publisher dashboard, only allow the
user to create runs for courses they have access to.

LEARNER-4102

This reverts commit 130654ab.
And commit 6662b884.

Couldn't test successfully on stage, so until I can confirm changes,
backing these out to not block others.

Ecommerce wants to talk to discovery to confirm details of course
like UUID. So let's publish to it after we publish to discovery.

When publishing a course run to ecommerce and discovery, also push
any entitlements for its course to those same services.

LEARNER-4031

Service users do not return any results for ApiAccessRequest. This
caused an index error which then prevented that result from being
cached.

When creating a new course in publisher, require type and price
up front rather than waiting until creating a course run. (only for
verified and professional courses)

And hide this feature behind a waffle flag.

LEARNER-3767

DJANGO_SETTINGS_MODULE in pytest.ini was being overriden by the
environment variable version of it. This overrides the setting in
the make command.

LEARNER-3769

Let's guard entitlement-creation support behind a waffle flag before
releasing it into the wild. So back it out now and we'll reintroduce
it after we have a flag.

When creating a new course in publisher, require type and price
up front rather than waiting until creating a course run.

LEARNER-3767

This fixes builds in travis. I specifically didn't change pylintrc
yet in this branch, to avoid having to fix all the new errors. But
I did make some of those  lint fixes anyway.