Update installing postgresql to work without firewall snippets

This ensures the snippets can be deleted when merging the port
procedures for installing.

Author: aneta-petrova

guides/common/modules/proc_installing-postgresql.adoc

@@ -13,8 +13,6 @@ ifndef::foreman-deb[]
 {Project} supports PostgreSQL version 13.
 endif::[]
 
-include::snip_firewalld.adoc[]
-
 .Prerequisites
 * The prepared host has base operating system repositories enabled.
 * The prepared host has sufficient disk space available for the `{postgresql-lib-dir}` directory.
@@ -85,13 +83,20 @@ password_encryption=scram-sha-256
 ----
 # systemctl enable --now postgresql
 ----
-. Open the *postgresql* port:
+. Update the firewall configuration.
+For example, using the `firewall-cmd` command:
+.. Open the *postgresql* port:
 +
 [options="nowrap" subs="verbatim,quotes"]
 ----
 # firewall-cmd --add-service=postgresql
 ----
-include::snip_make-firewall-settings-persistent.adoc[]
+.. Make the changes persistent:
++
+[options="nowrap", subs="+quotes,verbatim,attributes"]
+----
+# firewall-cmd --runtime-to-permanent
+----
 . Switch to the `postgres` user and start the PostgreSQL client:
 +
 [options="nowrap" subs="verbatim,quotes"]