Categories and subcategories shouldn't be hardcoded

### Describe the bug

Our tooling requires an enum from [CommunityToolkit.Tooling.SampleGen](https://github.com/CommunityToolkit/Labs-Windows/blob/2e2f317775ec51d0422b2564ad637538bbb94ddf/common/CommunityToolkit.Tooling.SampleGen/ToolkitSampleCategory.cs) to function.

Since the tooling is being shared between multiple repositories, this data needs to be dynamic. Categories and subcategories are only used to organize content in the sample app UI, and do not need to be hardcoded into the SampleGen tooling.

### Steps to reproduce

```text
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### Expected behavior

n/a

### Screenshots

_No response_

### Code Platform

- [ ] UWP
- [ ] WinAppSDK / WinUI 3
- [ ] Web Assembly (WASM)
- [ ] Android
- [ ] iOS
- [ ] MacOS
- [ ] Linux / GTK

### Windows Build Number

- [ ] Windows 10 1809 (Build 17763)
- [ ] Windows 10 1903 (Build 18362)
- [ ] Windows 10 1909 (Build 18363)
- [ ] Windows 10 2004 (Build 19041)
- [ ] Windows 10 20H2 (Build 19042)
- [ ] Windows 10 21H1 (Build 19043)
- [ ] Windows 11 21H2 (Build 22000)
- [ ] Other (specify)

### Other Windows Build number

_No response_

### App minimum and target SDK version

- [ ] Windows 10, version 1809 (Build 17763)
- [ ] Windows 10, version 1903 (Build 18362)
- [ ] Windows 10, version 1909 (Build 18363)
- [ ] Windows 10, version 2004 (Build 19041)
- [ ] Other (specify)

### Other SDK version

_No response_

### Visual Studio Version

_No response_

### Visual Studio Build Number

_No response_

### Device form factor

_No response_

### Additional context

_No response_

### Help us help you

Yes, but only if others can assist.

Inizia leggendo common/CommunityToolkit.Tooling.SampleGen/ToolkitSampleCategory.cs e tracciando come l'enum SampleGen viene utilizzato dal shared tooling e dalla sample app. Definisci da dove dovrebbero provenire categorie e sottocategorie, in modo che più repository possano usare il tooling; il lavoro è completato quando SampleGen non richiede più dati delle categorie hardcoded, mentre la sample app può continuare a organizzare i propri contenuti.

Scritto dal modello di indicizzazione a partire dal testo della issue.