Add opam package for stdlib + various fixes

This adds an opam package refinedrust-stdlib for the stdlib. Also, this fixes some things around the rr::context annotation, adds more later credits, and adds the static_has_refinement assertion to make timeless statements about refinements of statics.

case_studies/dune-project

+(lang dune 3.8)
+(using coq 0.8)
+(name refinedrust-examples)
+(package (name refinedrust-examples) (allow_empty))
+