Refactor Experiment endpoint and remove wtforms dependency

[alexb1200]

Removed wtforms forms and corresponding models. Made minimal changes to unit tests.

[jkglasbrenner]

@alexb1200 The refactored experiment tests in #322 have been merged to dev. There's a branch conflict because the old experiment unit test files were deleted and this branch makes edits to them. I'll resolve these conflicts and get this branch rebased so we can confirm if your refactor passes the new tests.

[jkglasbrenner]

Since this update changes the POST requests to no longer use forms, there are a couple places you'll need to update the Python client(s) (one being the deprecated client under examples/scripts/client.py). The first place is this:

dioptra/src/dioptra/client/_client.py

Lines 581 to 584 in 1e1b5ab

	response = requests.post(
	self.experiment_endpoint,
	data=experiment_registration_form,
	)

The second place is this:

dioptra/examples/scripts/client.py

Lines 146 to 149 in 1e1b5ab

	response = requests.post(
	self.experiment_endpoint,
	data=experiment_registration_form,
	)

Both need the following change:

        response = requests.post(
            self.experiment_endpoint,
-           data=experiment_registration_form,
+           json=experiment_registration_form,
        )

[jkglasbrenner]

There's a couple of small changes that are needed in schema.py to ensure that the Swagger documentation looks right. In addition, a couple of small changes are needed in the Python client, see the comment I left that points out what to change.

Outside of the above, this looks good. The changes are passing on the new integration tests, so once these changes are in place, I think we'll be good to merge.

[jkglasbrenner]

Looks good to me