[doc] How to configure admin only metadata through the config option

[Carlos Eduardo]

This is a documentation bug expected to track the admin only metadata configuration feature introduced in the Caracal (2024.1) release of Manila.

We should update our administrator references to reflect:

1. How to make a metadata option non-configurable by users;

Our user guide should have:

1. A new mention for users to check if some config options are available while mounting shares, as the share back ends might report this kind of thing from now on.

Our contributor guides should have:

1. A mention to how the driver can set metadata to the shares during the creation.

[Vida Haririan (vhariria)]

See additional triage information at https://meetings.opendev.org/meetings/manila/2024/manila.2024-03-14-15.00.log.html

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.opendev.org/c/openstack/manila/+/913845

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.opendev.org/c/openstack/manila/+/913846

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.opendev.org/c/openstack/manila/+/913845
Committed: https://opendev.org/openstack/manila/commit/e5e3b10656fa4f533e0499917757618573e2595f
Submitter: "Zuul (22348)"
Branch: master

commit e5e3b10656fa4f533e0499917757618573e2595f
Author: silvacarloss <email address hidden>
Date: Wed Mar 20 17:43:33 2024 -0300

    [doc] Admin only modifiable metadata

    Updates to the administrator and configuration metadata to address
    the new configuration option, which allows administrators to
    specify metadata items that should not be updated by less
    privileged users.

    Signed-off-by: silvacarloss <email address hidden>

    Partial-Bug: #2057707
    Change-Id: If8d51d50630f0581d588e07c3c086442b451c360

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.opendev.org/c/openstack/manila/+/913846
Committed: https://opendev.org/openstack/manila/commit/dd615466ef4fd723feb19f414d96d8032c7ebe8e
Submitter: "Zuul (22348)"
Branch: master

commit dd615466ef4fd723feb19f414d96d8032c7ebe8e
Author: silvacarloss <email address hidden>
Date: Wed Mar 20 17:46:36 2024 -0300

    [doc] Mount options in the ceph native driver

    CephFS native shares will now have the cephfs filesystem name
    added to its metadata through `__mount_opts`.

    We are also warning and instructing administrators how to prevent
    less privileged users to update such metadata.

    Signed-off-by: silvacarloss <email address hidden>

    Closes-Bug: #2057707
    Change-Id: Ica80d80d9a3709814c1ba1c9e5d942ab0c97aec7