feat: add a configuration option to open the endpoint /uuid to other … (backport #136) (#185)

This is an automatic backport of pull request #136 done by [Mergify](https://mergify.io).
Cherry-pick of 9d71702 has failed:
```
On branch mergify/bp/release_0.8/pr-136
Your branch is up to date with 'origin/release_0.8'.

You are currently cherry-picking commit 9d71702.
  (fix conflicts and run "git cherry-pick --continue")
  (use "git cherry-pick --skip" to skip this patch)
  (use "git cherry-pick --abort" to cancel the cherry-pick operation)

Changes to be committed:
	modified:   config/nginx.conf

Unmerged paths:
  (use "git add/rm <file>..." as appropriate to mark resolution)
	deleted by us:   config/config.ini.custom

```


To fix up this pull request, you can check it out locally. See documentation: https://help.github.com/articles/checking-out-pull-requests-locally/

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Author: mergify[bot]

config/config.ini

@@ -151,6 +151,13 @@ storage_min_delete_depth=0
 # (see http://nginx.org/en/docs/http/ngx_http_autoindex_module.html)
 storage_autoindex=1
 
+# extra networks allowed on /uuid endpoint (in addition to 127.0.0.1/32)
+# (coma separated list)
+# ("null" => no extra uuid allowed)
+# example : 
+# uuid_endpoint_extra_allows=5.6.0.0/16,1.2.3.4/32
+uuid_endpoint_extra_allows=null
+
 
 #######################
 ##### AUTORESTART #####

config/nginx.conf

@@ -40,6 +40,13 @@ http {
         # FIXME: rename this in __uuid
         location = /uuid {
             allow 127.0.0.1/32;
+        {% if MFBASE_NGINX_UUID_ENDPOINT_EXTRA_ALLOWS != "null" -%}
+            {% for ALLOW in MFBASE_NGINX_UUID_ENDPOINT_EXTRA_ALLOWS.split(',') %}
+                {%- if ALLOW != "" -%}
+                    allow {{ALLOW}};
+                {% endif %}
+            {%- endfor -%}
+        {%- endif -%}
             deny all;
             echo "{{UUID}}";
             access_log off;