Add filters to "Browse Plugins" in DMS to match the website

### Feature Description

Since the DMS plugin registry is getting large (which is very good), it could be more easily browsable from the 'Browse plugins' window, like filtering by categories or by compositor, for example.

### Use Case

_No response_

### Compositor(s)

All compositors

### If Other, please specify

_No response_

### Proposed Solution

_No response_

### Alternatives/Existing Solutions

_No response_

Start at the DMS “Browse plugins” window and inspect how the plugin registry is presented. Determine which filtering dimensions and user-visible behavior are required, then verify that categories or compositor filters make the growing registry easier to browse.

Written by the indexing model from the issue text.