Better support of read only config file

[DeepDiver1975]

Description

This change adds a better support and handling of a read only config file

Motivation and Context

We need to support clustered setups better - in these setups the config file is not writable

How Has This Been Tested?

• add 'config_is_read_only' => true to config.php
• see the changed mail settings section

Screenshots (if appropriate):

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have read the CONTRIBUTING document.
• I have added tests to cover my changes.
• All new and existing tests passed.

[PVince81]

👍 I remember this code

[PVince81]

@DeepDiver1975 please backport

[lock]

This thread has been automatically locked since there has not been any recent activity after it was closed. Please open a new issue for related bugs.