remove libbitcoinconsensus

This was deprecated in v27.0, for removal in v28.0.
See discussion in PR #29189.

doc/README.md

@@ -59,7 +59,6 @@ The Bitcoin repo's [root README](/README.md) contains relevant information on th
 - [Translation Strings Policy](translation_strings_policy.md)
 - [JSON-RPC Interface](JSON-RPC-interface.md)
 - [Unauthenticated REST Interface](REST-interface.md)
-- [Shared Libraries](shared-libraries.md)
 - [BIPS](bips.md)
 - [Dnsseed Policy](dnsseed-policy.md)
 - [Benchmarking](benchmarking.md)