cmd/geth: implement vulnerability check (#21859)

* cmd/geth: implement vulnerability check

* cmd/geth: use minisign to verify vulnerability feed

* cmd/geth: add the test too

* cmd/geth: more minisig/signify testing

* cmd/geth: support multiple pubfiles for signing

* cmd/geth: add @holiman minisig pubkey

* cmd/geth: polishes on vulnerability check

* cmd/geth: fix ineffassign linter nit

* cmd/geth: add CVE to version check struct

* cmd/geth/testdata: add missing testfile

* cmd/geth: add more keys to versionchecker

* cmd/geth: support file:// URLs in version check

* cmd/geth: improve key ID printing when signature check fails

Co-authored-by: Felix Lange <fjl@twurst.com>