Make ElasticSearch aggregate search results size configurable

AGGREGATE_PAGE_SIZE defaults to 10, which matches the elasticsearch_dsl default.

* Add exception arg to handler404 function signature

* Use the underscore var for unused exception arg

* Make exception arg an unused keyword arg

Change edx-django-release-util version.

* Replace "Starting Soon" -> "Upcoming" availability

"Starting Soon" is still stored in the database, but it is collapsed into
the "Upcoming" category in the API view response.

* Test that Starting Soon is unioned with Upcoming

Update openedx.yaml to reference master branch

We no longer use the "release" branch

Use old-style course ID for fake data in Travis

Also change option name course_id to course-id to consistently use hyphens in
option parameters.

Add --no-videos option to generate_fake_course_data command

Add "analyticsapi" to local ALLOWED_HOSTS setting

Also fix a spelling mistake for default course-id value in
generate_fake_course_data.py script.

AN-7775 Generate local video data

Document manual OAuth steps in README. Add clients/utils.py to
analyticsdataserver with tests.

The travis target should install the test requirements as well as the…

Moving to running analytics tests on 16.04

This commit also switches us from coveralls to codecov.

Updated field names in course summaries.

* renamed start/end_time to start/end_date
* renamed modes to enrollment_modes

Change edx-django-release-util version.

Adds the course metadata enrollment summary endpoint.

* Refactored tests to use a variety of course IDs using ddt
* Bump versions of opaque keys and ccx libraries
* Added timeout check to see if the elasticsearch index is ready in tests (fixes flaky tests)

AN-7880 Uncomment including "posted_forum" events

Change edx-django-release-util version.