feat:(dms-integration): Add dms-integration extension

[AurelienJt]

DankMaterialShell Vicinae Integration

Hello, this draft PR aims to determine if adding an extension integrating DMS functionalities and tools into Vicinae would make sense.

The Extension adds the following commands. (More detail in the extension README.md)

Search Files: Searched files using the integrated DMS search utility (dsearch). It also allows narrowing down the search scope with an optional argument. For DMS users, relying on the native tools is a huge convenience, as we expect the same search results and configuration methods across the DMS experience.

Reindex Files for Search Triggers async re-index with the user deciding if index should be fully rebuilt or simply updated using the option dropdown.

Settings: Opens the DMS settings, which for some reason don't include a .desktop file by themselves.

Note: The DMS file search indirectly re-implements Vicinae's file search. As such, I'll let the maintainers decide if adding this extension to the store makes sense. However, I stress the convenience of DMS users to be able to only use 1 file search accross the OS. Also, currently the DMS search command is named the same as the native one. This could be changed.

ToDo: Some errors can become too long to be displayed as toasts. Also, toasts disappear very quickly, making the error difficult to read.