We have three different ways of checking the formats of datetimes.
1. The built-in way that comes with the jsonschema package ("date-time")
2. A new way we added for broadcasts ("datetime") 61a5730596
3. An old way we defined in
"/tests/app/public_contracts/schemas/v0/definitions.json"
In order to simplify things and make it clearer how datetimes are being
validated, this replaces the few places where we were using option 3 with option 1
instead. Option 3 was only being used to validate code that is no longer
used, the initial version of the API.
Emualated the validation methods that exist [in the python-client](620e5f7014/integration_test/__init__.py).
The `validate_v0` function loads json schemas from a local
`/schemas` directory, whereas the new `validate` function (which
we're going to use for our v2 API calls) uses the common
`get_notification_response` python schema defined in
"app/v2/notifications/notification_schemas.py".
Removed the new `v2` schema from the last commit as it's no longer
being used.
Also, refactored common code in the GET and POST contract files
so that making requests and converting responses to JSON are
pulled out into common functions.
