[6788][ADD] maintenance_request_done_readonly

[smorita7749]

QT6788

[smorita7749]

Pushed bc20921b3 to 6788-add-maintenance_request_done_readonly, reflecting the current state of the upstream PR OCA/maintenance#578 (module now identical to that branch).

What changed:

• Configuration: dropped the res.config.settings UI (models/res_config_settings.py, views/res_config_settings_views.xml) in favour of editing the maintenance_request_done_readonly.editable_fields system parameter directly (created on install via data/ir_config_parameter.xml).
• Access: added a dedicated group Maintenance: Edit Completed Requests (security/res_groups.xml), implied by maintenance.group_equipment_manager. The write lock now checks that group instead of the equipment manager group, so the permission can be granted without making the user a maintenance manager.
• write(): the always-writable set is reduced to message_main_attachment_id plus the parameter-configured fields, the mnt_done_bypass_lock check moved first, and the code was simplified (walrus for the locked records, plain super()).
• Tests: assert that managers imply the new group, and that a non-manager user holding the group can edit a completed request.
• Docs (readme/DESCRIPTION.md, README.rst, static/description/index.html) and the manifest summary updated to the new behaviour.

 maintenance_request_done_readonly/README.rst       | 13 +++--
 maintenance_request_done_readonly/__manifest__.py  |  5 +-
 .../data/ir_config_parameter.xml                   |  7 +++
 .../models/__init__.py                             |  1 -
 .../models/maintenance_request.py                  | 67 +++++++++-------------
 .../models/res_config_settings.py                  | 38 ------------
 .../readme/DESCRIPTION.md                          | 12 ++--
 .../security/res_groups.xml                        | 18 ++++++
 .../static/description/index.html                  | 13 +++--
 .../test_maintenance_request_done_readonly.py      | 22 +++++++
 .../views/res_config_settings_views.xml            | 26 ---------
 11 files changed, 104 insertions(+), 118 deletions(-)