Implement Auth0 mock server for local development

[ygrishajev]

To make sure anyone can develop features which require auth we can do 2 things: share our dev env secrets or implement a mock server into our docker compose setup. The 1st one is not always desirable, however the last one would work in any case.

Acceptance criteria:

• investigate possible solutions. One I found quickly is https://github.com/primait/localauth0
• add it to our docker compose setup
• update apps to use it for local development (readmes, .env.local.sample)