Export mapped variants and add README for public data dump#728

bencap wants to merge 2 commits intorelease-2026.2.1VariantEffect/mavedb-api:release-2026.2.1from

feature/bencap/664/include-mapped-variants-in-dumpVariantEffect/mavedb-api:feature/bencap/664/include-mapped-variants-in-dumpCopy head branch name to clipboard