Configuration option to suppress product name when querying the directory ressource

[grindsa]

new parameter suppress_product_information in acme_srv.cfg to suppress product, author, homepage and version number as below...

{
    "newAuthz": "http:/URL/acme/new-authz",
    "newNonce": "http://URL/acme/newnonce",
    "newAccount": "http://URL/acme/newaccount",
    "newOrder": "http://URL/acme/neworders",
    "revokeCert": "http://URL/acme/revokecert",
    "keyChange": "http:/URL/acme/key-change",
    "renewalInfo": "http://URL/acme/renewal-info",
    "meta": {
        "externalAccountRequired": true,
    },
    "2737bf72b19c40398a678f5a1f644d8a": "https://community.letsencrypt.org/t/adding-random-entries-to-the-directory/33417"
}