Create article about passwords

The main goal of this page should be:

describe that there is no default password and user sets password in the wizard, also describe the difference between Foris and system password
describe how are these passwords stored and what encryption/hash function is used (/etc/shadow and /etc/config/foris auth.password)
describe how to change the password (system and password for foris)

This should help meet the following mandatory requirements for Tier 1 defined by CSA Singapore's Cybersecurity Labeling Scheme

5.1-1:Where passwords are used and in any state other than the factory default, all consumer IoT devicepasswords shall be unique per device or defined by the user.
5.1-3:Authentication mechanisms used to authenticate users against a device shall use best practice cryptography, appropriate to the properties of the technology, risk, and usage.
5.1-4:Where a user can authenticate against a device, the device shall provide to the user or an administratora simple mechanism to changethe authentication value used.

Edited Oct 27, 2020 by Jan Pavlinec