[top_darjeeling] Alternative boot topology

[tjaychen]

desc

Create a general framework showing how the proposed boot topology can be applied to systems with different requirements.

Specifically

• how it could be made compatible with systems with legacy security assumptions
• how the bootstrap process would work and how it ties into measurements and verification
• how OT needs control of resets to streamline downstream behavior
• Clarify what "other ROMs" really mean.

See notes here, restricted audience

[tjaychen]

Please see additional samples for alternative boot topology

@moidx @cfrantz @johannheyszl