[#5154] Enable certificate verification (incl. revocation) on Docker (#5159)
[#5154] Enable certificate verification (incl. revocation) on Docker (#5159)

o Install `openssl` as part of `.certbot-deps`
o `certbot` on Docker container uses `openssl` to verify certificate
stweil/letsencrypt,jsha/letsencrypt,jsha/letsencrypt,stweil/letsencrypt,lmcro/letsencrypt,letsencrypt/letsencrypt,lmcro/letsencrypt,letsencrypt/letsencrypt