Add Write access permission to Access Synchronisation

We have a request from a Matomo user to add an additional access field to the Access Synchronisation settings for the `Write` permission.

Currently the plugin only supports `View`,`Admin`, and `Super User`
This means that for many Matomo admins that use this feature, they still need to manually manage the Write access permission through the Matomo UI

Start by locating the Access Synchronisation settings and the existing View, Admin, and Super User permission handling in the plugin. Trace how those fields are stored and applied, then add the corresponding Write option. Done means administrators can configure and synchronize Write access without managing it manually in Matomo.

Written by the indexing model from the issue text.