Bring in keys / signature page
After !26 (merged) is merged, basically copy-paste https://git.glasklar.is/system-transparency/core/system-transparency/-/blob/main/keys/README.md?ref_type=heads into release process docs.
After !26 (merged) is merged, basically copy-paste https://git.glasklar.is/system-transparency/core/system-transparency/-/blob/main/keys/README.md?ref_type=heads into release process docs.