Tracking issue for RFC 66: Simulation time.

[zyp]

• RFC PR: RFC #66: Simulation time rfcs#66
• Implementation PR: Implement RFC 66: Simulation time. #1461
• Documentation PR: N/A
• Removal of deprecation PR: N/A

[whitequark]

@zyp Please send PRs addressing the downstream warnings in amaranth-stdio and amaranth-soc, since right now these always fail smoke test.

[zyp]

Will do!