refactor: refactor file service for app data

[pyphilia]

I moved from

.
├── item/plugins/app/appData         
│   ├── index.ts   
│   ├── schemas.ts   
│   ├── service.ts   
│   ├── plugins/file
│       ├── index.ts
│       ├── service.ts
├── ...

to

.
├── item/plugins/app/appData         
│   ├── index.ts   
│   ├── schemas.ts   
│   ├── service.ts    
│   ├── appDataFileServiceAdapter.ts    
├── ...

This change is motivated by removing hooks.

The original idea was to have a separated plugin, so that it is easy to remove if we don't need it.
We now take the assumption file for app data is a core feature, so I merged both plugins.
AppDataService now has a AppDataFileServiceAdapter. This service is in charge of reusing a FileService for the purpose of app-data.

ref #1635

[sonarqubecloud]

Quality Gate passed

Issues
3 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
10.6% Duplication on New Code

See analysis details on SonarQube Cloud

[spaenleh]

Changes look good ! Thank you for this refactor !

[sonarqubecloud]

Quality Gate passed

Issues
2 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
8.8% Duplication on New Code

See analysis details on SonarQube Cloud