Reduce permissions to this org/repo

In the rush to set this repo up and make bulk changes, extensive permissions were given. Actions that should be taken:

# Reduce repo specific permissions
We currently have

```yaml
github-mgmt:
collaborators:
admin:
- andyschwab-admin
- arajasek
- galargh
- jennijuju
- JesseXie
- mastrwayne-admin
push:
- autonome
- mroth
- scotthconner
- web3risk-admin
```

Lets remove all the direct collaborators.
We can move these folks to the github-mgmt team:
- andyschwab-admin
- arajasek
- jennijuju
- mastrwayne-admin
since they are already owners per https://github.com/orgs/filecoin-project/people?query=role%3Aowner

I believe the rest can be dropped.

# Remove org ownership
In this event @galargh and I were elevated to org owners. We should be removed. With github-mgmt setup and having access there, we should be self-sufficient in helping with future permission needs.