Undo TQ unplumbing

[AlejandroME]

As part of the ongoing IPCC troubleshooting and mitigation for R18 (see stlouis#912, #918, #925, we are temporarily disabling Trust Quorum.

This issue tracks the work required to revert this work and restore TQ.

[jgallagher]

#9836 disabled Trust Quorum; however, we do still use IPCC (including the large RoT request that has been on the scene with many of the observed problems) when setting up sled-agent for the first time, which happens both during RSS and during a "sled add" procedure:

• Setting up a sprockets server with our sprockets config
• Sprockets config where we instruct it to use IPCC (we have no other option for production)
• Sprockets handshake, which I believe is the point where we'd send an IPCC request for RoT certs
• The resulting connection is only used to start for the first time sled-agent; i.e., during RSS or "sled add"

[andrewjstone]

Done.