Add option to select algorithm to generate ACME certificates

docs/configuration/acme.md

@@ -86,6 +86,15 @@ entryPoint = "https"
 #
 # caServer = "https://acme-staging-v02.api.letsencrypt.org/directory"
 
+# KeyType to use.
+#
+# Optional
+# Default: "RSA4096"
+#
+# Available values : "EC256", "EC384", "RSA2048", "RSA4096", "RSA8192"
+#
+# KeyType = "RSA4096"
+
 # Domains list.
 # Only domains defined here can generate wildcard certificates.
 #