Allow configuration of ACME provider http timeout

docs/content/https/ref-acme.toml

@@ -30,6 +30,20 @@
   #
   # certificatesDuration=2160
 
+  # Timeout for a complete HTTP transaction with the ACME server.
+  #
+  # Optional
+  # Default: 2m
+  #
+  # clientTimeout="2m"
+
+  # Timeout for receiving the response headers when communicating with the ACME server.
+  #
+  # Optional
+  # Default: 30s
+  #
+  # clientResponseHeaderTimeout="30s"
+
   # Preferred chain to use.
   #
   # If the CA offers multiple certificate chains, prefer the chain with an issuer matching this Subject Common Name.