- bind_set_new_serial.sh, bind_set_renew_tlsa.sh: redesign code, add configuration file support

- Add 'script bind_rndc_sync_clean.sh'.
- bind_get_domain_by_hostname.sh: minor changes at code order.
- Adjust sample configuration file 'bind.conf.sample'.

conf/bind.conf.sample

@@ -4,6 +4,24 @@
 # ---
 # ----------------------------------------------------
 
+# - BIND_USER
+# -
+# - The user under which the nameservice is running
+# -
+# - Defaults to 'bind'
+# -
+#BIND_USER=bind
+
+
+# - BIND_GROUP
+# -
+# - The group under which the nameservice is running
+# -
+# - Defaults to 'bind'
+# -
+#BIND_GROUP=bind
+
+
 # - CONF_FILE_DIR
 # -
 # - Directory containing bind configuration files