Compatibility with Generate Password module

Problem/Motivation

This module provides the [user:password] token, and also hides the password field and forces the generation of a password.

The Generate Password module primary does the 2nd/3rd part of that by always generating a password for an account and optionally hiding the fields. It has also provided the [user:password] token but is now looking to remove that support, pointing admin needing the functionality here: #3495763: Remove broken [user:password] token

Unfortunately the two modules do not work kindly together with RPT overriding Generate Password's settings in regards to the password field and generating the password again. Depending on execution order, it results in unpredictable results.

Steps to reproduce

- Install both modules.
- Configure Generate Password to provide the password field for optional password entry, with user notification of a generated password.
- Randomly will either have a password field, or the password display to the user does not work as two passwords were generated, one display the other set.

Proposed resolution

Remove the password field handling in this module, suggesting to users if they continue to want that functionality to install Generate Password which does the same thing.

Remaining tasks

- Remove settings:
- password_generate
- password_length
- (associated schema)
- Remove settings from form
- Add information on a different module to use for that functionality
- Do not alter the password field
- Do not generate a password if a password has already been generated for the user, or the user has entered their own passwords
- Add tests to confirm interoperability with genpass in both genpass and rpt

User interface changes

Settings have been removed. Added info on where they can be obtained.

API changes

n/a

Data model changes

n/a