Improve the http-01-echo example

If someone used the example the way it was defined, file-access issues
may arise. This new example add two new hooks to fix it. The example
should now work in most environment although the path may need to be
adapted.

man/en/acmed.toml.5

@@ -363,16 +363,38 @@ to solve the
 challenge and
 .Xr rm 1
 to clean it.
+.Xr mkdir 1
+and
+.Xr chmod 1
+are used to prevent issues related to file access.
 .Bd -literal -offset indent
 [[hook]]
-name = "echo"
+name = "http-01-echo-mkdir"
+type = ["challenge-http-01"]
+cmd = "mkdir"
+args = [
+    "-m", "0755",
+    "-p", "/var/www/{{domain}}/.well-known/acme-challenge"
+]
+
+[[hook]]
+name = "http-01-echo-echo"
 type = ["challenge-http-01"]
 cmd = "echo"
 args = ["{{proof}}"]
 stdout = "/var/www/{{domain}}/.well-known/acme-challenge/{{file_name}}"
 
 [[hook]]
-name = "echo-clean"
+name = "http-01-echo-chmod"
+type = ["challenge-http-01-clean"]
+cmd = "chmod"
+args = [
+    "a+r",
+    "/var/www/{{domain}}/.well-known/acme-challenge/{{file_name}}"
+]
+
+[[hook]]
+name = "http-01-echo-clean"
 type = ["challenge-http-01-clean"]
 cmd = "rm"
 args = [
@@ -381,15 +403,20 @@ args = [
 ]
 .Ed
 .Pp
-The two above hooks can be grouped in order to reduce the number of hooks to define in the certificate.
+The hooks from the previous example can be grouped in order to reduce the number of hooks to define in the certificate.
 .Bd -literal -offset indent
 [[group]]
-name = "http-echo"
-hooks = ["echo", "echo-clean"]
+name = "http-01-echo-var-www"
+hooks = [
+    "http-01-echo-mkdir",
+    "http-01-echo-echo",
+    "http-01-echo-chmod",
+    "http-01-echo-clean"
+]
 
 [[certificate]]
 # Some fields omitted
-hooks = ["http-echo"]
+hooks = ["http-01-echo-var-www"]
 .Ed
 .Pp