Archived repositories cannot be modified - stop configuring them through github-mgmt

[galargh]

Since archived repositories cannot be modified - there's no need to control anything beyond their archived status through github-mgmt.

#19

[galargh]

I created a support ticket because some actions on archived repos are allowed through the UI but disallowed through the API. The support tickets are private so I'll update this issue once I hear back from the team.

[achingbrain]

We created https://github.com/ipfs-inactive as a place to put old ipfs repos that are no longer maintained to keep the repo list in shape - maybe we need libp2p-inactive too?