Default password should be random

User Story

As a Ryax Admin, I want to the default password to be randomized, so there is no unauthorized access to my fresh installation.

The current default credentials are hard coded into Ryax if not found in the database. This is a security flaw and should be removed. Instead, it should load the default password from a randomly generated secrets provided by Kubernetes secret.

Recipes and tests

Create a new install and get the command to get the secret from the Helm NOTE.md

Get the secret and test that it works to log in.

Changing the password should be possible with a warning saying that it will override the value from the secret.

Is it a breaking change? Why?

Only doc

What is it good for?

Security: improve Ryax security