Restructure the repository

- Make OpenPGP only one of many protocols
  + KEYS.md only holds the current keys
  + OPENPGP.md describes all OpenPGP details
- Make the current public key available at the root
- Add scripts/ to automate the various steps:
  + bootstrap.sh
  + publish.sh
  + sign.sh
  + snapshot.sh
  + verify.sh

OPENPGP.md.asc

@@ -0,0 +1,7 @@
+-----BEGIN PGP SIGNATURE-----
+
+iHUEABYKAB0WIQTW0Zid8fayP9d2KT20bttN/CaAXQUCarGC1AAKCRC0bttN/CaA
+XS5IAQDcDzL+O2P0LvrrDvTiLPme2mcyAifUCbCCNSnHXjzerQEA5TAwKK0ktW29
+7yDzIi4T+uQ0kAttq91U6oIT8Wzb1QM=
+=VAgU
+-----END PGP SIGNATURE-----