Release v2

[icweaver]

• Synchronize Astrometry.jl
• Archive ERFA.jl / point to SOFA.jl
• Update JuliaAstro website (docs: Update SOFA.jl to v2 JuliaAstro.github.io#213)
• Update SOFA IAU page (Migrate pure-Julia SOFA implementation from Astrometry.jl (v2.0) #38 (comment))
• Increase test coverage
• Improve docs
• Format with Runic.jl
• Update license
• Register
• Discourse / Bluesky post
  • Related Discourse post: https://discourse.julialang.org/t/ann-erfa-jl-1-0-and-1-1-essential-routines-for-fundamental-astronomy/65424