Add a central registry of all templates that exist

### TL;DR

We could create a central registry (or multiple registries) probably in the form of a YAML file, of all the templates that are known to exist.

### Detailed design

```markdown
Desired features:
- Support public and private (my company only) registries
- Searching
- Tagging by language, purpose, framework, etc
- Easy updating/publishing of templates
```

### Alternatives considered

```markdown
Just have users discover template URLs via docs, word of mouth, etc.
```

### Additional information

_No response_