Splits docs to use three different `permalink` paths:
- `/raw/`
- `/draft/`
- `/stable/`
Otherwise docs like these clash and only one is accessible:
```
docs/draft/3-whisper-usage.md
docs/stable/3-whisper-usage.md
```
```
docs/draft/6-payloads.md
docs/stable/6-payloads.md
```
Signed-off-by: Jakub Sokołowski <jakub@status.im>