Blender: ops refresh manager after process events

[kaamaurice]

Brief description

Blender host ops module enhancements : manager refresh after process events

Description

• Manager (scene inventory) is refreshed after process events.
• _process_app_events registered once (before, this was multiple registered, each time OP dialogs was opened)
• TIMER_INTERVAL more longer to avoid lag with MacOs.
• OP Blender startup add-on fixed with required function register/unregister.

Testing notes:

1. Open a task with out-to-date OP container asset.
2. Open the Manager dialog and update the asset.
3. Should get the Manager refreshed after the update.