Add a Uri prop to choose between production or staging CA

And default to staging

root/etc/e-smith/db/configuration/defaults/letsencrypt/Uri

@@ -0,0 +1 @@
+staging

root/etc/e-smith/templates/etc/letsencrypt.sh/config.sh/10Uri

@@ -0,0 +1,14 @@
+{
+
+my $uri = $letsencrypt{'Uri'} || 'staging';
+if ($uri =~ m{^https?://}){
+  $OUT .= "CA=$uri\n";
+}
+elsif ($uri =~ m/^(test(ing)?)|staging$/){
+  $OUT .= "CA=https://acme-staging.api.letsencrypt.org/directory\n";
+}
+elsif ($uri =~ m/^prod/){
+  $OUT .= "CA=https://acme-v01.api.letsencrypt.org/directory\n";
+}
+
+}