Improvements in local setup instructions

[hussamkhatib]

Is your proposal related to a problem?

The section Setup your first user is not required imo. There are already all kinds of users created using the seed data

Describe the solution you'd like

Replace that section with paragraph describing how to quickly sign in as a particular user.

[PeerRich]

we're working on better DX getting started docs, cc @alishaz-polymath

[alishaz-polymath]

This should be resolved quite soon. 🙏 Thank you for waiting

[alishaz-polymath]

The Setup your first user step is actually useful in case yarn dx isn't used for a quick setup, which requires Docker and Docker Compose. As for signing in from various users, the notes specify that the credentials are logged and available on the console when running yarn dx