acme: Support running in webroot mode, detect other daemons on port 80

For configurations where another web server is running on port 80, running
acme.sh in standalone mode fails. Try to detect this and refuse to run; and
allow the user to configure a webroot directory to use the running webserver for
certificate verification.

This also updates acme.sh to the latest version.

Signed-off-by: Toke Høiland-Jørgensen <toke@toke.dk>

net/acme/files/acme-cbi.lua

@@ -25,11 +25,12 @@ s.anonymous = true
 st = s:option(Value, "state_dir", translate("State directory"),
               translate("Where certs and other state files are kept."))
 st.rmempty = false
-st.datatype = "string"
+st.datatype = "directory"
 
 ae = s:option(Value, "account_email", translate("Account email"),
               translate("Email address to associate with account key."))
 ae.rmempty = false
+ae.datatype = "minlength(1)"
 
 d = s:option(Flag, "debug", translate("Enable debug logging"))
 d.rmempty = false
@@ -56,6 +57,12 @@ u = cs:option(Flag, "update_uhttpd", translate("Use for uhttpd"),
                         "(only select this for one certificate)."))
 u.rmempty = false
 
+wr = cs:option(Value, "webroot", translate("Webroot directory"),
+               translate("Webserver root directory. Set this to the webserver " ..
+                         "document root to run Acme in webroot mode. The web " ..
+                         "server must be accessible from the internet on port 80."))
+wr.rmempty = false
+
 dom = cs:option(DynamicList, "domains", translate("Domain names"),
                 translate("Domain names to include in the certificate. " ..
                           "The first name will be the subject name, subsequent names will be alt names. " ..