full-install: add letsencrypt cert gen script

docker-compose/full-install/nginx/conf-templates/certbot_conf.template

@@ -0,0 +1,15 @@
+server {
+    listen 80;
+    listen [::]:80;
+    
+    # chantge server_name while generating cert
+    server_name <SERVER_NAME>;
+
+    #access_log  /var/log/nginx/host.access.log  main;
+
+    # this is required for cert generation. 
+    # change server_name as well with cname of required cert
+    location /.well-known/acme-challenge/ {
+        root /var/www/certbot;
+    }                     
+}