Wipe and restart

[jku]

I plan to nuke this repository and start over:

• plan is still for this to be a long lived TUF repository that tests/demos/etc can trust to exist in a valid state
• tuf-on-ci is the tooling I want to use for that
• Importing the current repository metadata is possible but I won't do that because
  • some changes are going to be needed anyway (like succinct delegations will go away)
  • I don't want to spend the time on tweaking that

So apologies for the disruption but this repository will start again with new 1.root.json today.

1607 timestamp versions and 2 years was a decent run for this version.

[jku]

My plan based on last 2 years of experience makes the key setup look a little different from a "production repo":

• root has multiple signers, threshold 1
• root threshold is kept low as
  • the security is not that critical: this is not a production repo
  • the keys are likely low value keys that may get lost or wiped, maintainer attention is likely fleeting
• delegated roles can have more interesting threshold setups for testing
• anyone in the TUF community who wants to add things to a live repository can become a signer