Merge #11380: Remove outdated share/certs/ directory

6951a1c Remove extremely outdated share/certs dir (MeshCollider)

Pull request description:

  The directory hasn't been touched for 5 years (other than a couple of typo fixes/renaming). The certificates are expired, the build process notes are out of date, especially with the gitian building and everything, Gavin no longer has anything to do with it, etc.

  The signing process is all documented (and scripted) elsewhere (e.g. doc/release-process.md and gitian-building.md, contrib/macdeploy and windeploy), this can just be removed

  @theuni can confirm if this is okay, we discussed it on IRC for a bit :)

Tree-SHA512: e229785f7514a0f9988105f2ce68531a0a876032983ee5c77f41f1a976b9e732eb63cf2eb1f82841df8f7194940635c5ea5d4f8b30f95e69c763f74d4a3a28b1

Author: laanwj