Allow a default user account that doesn't require login

**Proposal:**
Allow a default user account that doesn't require login.

**Current behavior:**
A username and password is required to access the influx UI

**Desired behavior:**
If enabled, when a user tries to access the UI it will automatically log them in to a default user account. They can then login in to a different account if they wish.

**Alternatives considered:**
Ability to pass login information to the sever using the URL. This would reduce the work required for the feature to work but could be a security risk.

**Use case:**
Make it easier to just share a link to a dashboard without having to provide them with login information.
Could reduce issue with having a dashboard permanently displayed on a monitor that doesn't have input device.

Happy to answer any questions about this request.