Support Dash v2

[jlondonobo]

What it does

1. Add support for dash v2 imports (from dash import html, dcc).
2. Fix test errors in test_api_requests.py.
3. Set store_test_results in .circlei/config.yml to store test results for easier debugging.

How is this helpful
No more import warnings: the dash_html_components package is deprecated. Please replace import dash_html_components as html ... when using dash-auth.

Context
This PR is meant to solve #121. #122 was on the right path so I based myself in that PR.

Next steps
There are still 19 failed tests which I think are all caused by the same problem The users dict is widely used throughout test_plotly_auth_integration.py but it requires environmental variables that are never defined (I could have missed something).

Thus, test such as this will fail

[lambda-science]

Any updates on merging this branch ?

[ColinMaudry]

Maybe @os185059 or @alexcjohnson can merge it?

[3tilley]

It would be great for us if this could be resolved

[Mo-Bud]

Agreed it would be helpful for this to get reviewed as the warning is pretty annoying.

[alexcjohnson]

@jlondonobo apologies that we missed this for so long. I'm going to close it and make a new PR though, because the entire PlotlyAuth class (along with all the JS it entails) is long obsolete - a relic of an old version of our enterprise product that literally no customer is using anymore. That will dramatically simplify this repo.