Exclude selected repos in suborgs level

## New Feature

prodivde a way to exclude selected repos from suborgs level (aka team level).

Why?

We have some repos with multiple collaborators (A anb B). If A already created a suborg config file, B can't create anymore because the shared repo was already configured with A.

Error example frorm safe-settings:
```
❗ Error: Multiple suborg configs for repo-a in .github/suborgs/A.yml and .github/suborgs/B.yml
```

The suggestion is:
```yaml
suborgteams:
- B
exclude:
- repo-a # because it is already configued with team A
```