[Canvas] Unify storybook example sets

[poffdeluxe]

When storybook for everyone was merged, we agreed to keep around a few Canvas stories separately from the new storybook set because of some special mocking/handling that happens in the special Canvas set.

We should work towards getting rid of the old Canvas storybook set so that Canvas only has one set of storybook tests.

The problems that exist (afaik) that are preventing us from moving over:

1. Some components have pieces that require some sort of new platform context
2. Some components have children components that import from a platform API and we don't want to pull in all that code or rely on that unmocked API
3. Some components have children components that pull in redux state

[elasticmachine]

Pinging @elastic/kibana-canvas (Team:Canvas)

[ThomThomson]

Closing this for now as we are no longer prioritizing Canvas storybooks.