Incremental plugin scan

[DropSnorz]

A new plugin scan can be implemented to avoid running Native Discovery on the entire plugin set. Running Native Discovery can take from 1s to 3s, leading to huge execution time for people collecting more than 1.000+ plugins.

An incremental scan will detect:

• Added plugins, from OwlPlug or manually
• Deleted plugins, from OwlPlug or manually
• Deactivated plugins (using .deactivated extension) from OwlPlug or manually

An incremental scan won't detect an updated plugin file either by OwlPlug or manually.

[kmturley]

Here is a link to the scan logic in Open Audio Stack: https://github.com/open-audio-stack/open-audio-stack-core/blob/main/specification.md#scan-logic