[MONIT-4106] docs/logs/fluentbit: add values provided lua scripts section

docs/logs.md

@@ -101,6 +101,21 @@ outputs: |
       http_passwd {{ .Values.tenant.password }}
 ```
 
+### Fluentbit Custom Lua Scripts
+In Fluent Bit we can use Lua scripts to create processors that transform the records. These scripts are available in the Fluent Bit container under the path `/fluent-bit/etc/scripts`. In order to create new Lua scripts just add them in the values `logs.fluentbit.luaScripts` key.
+
+For example, the following configuration will create two files in `/fluent-bit/etc/scripts`. One named `my_lua_script.lua` and another one named `my_lua_script2.lua`.
+```yaml
+luaScripts:
+  my_lua_script.lua: |
+    function my_function(tag, timestamp, record)
+      // Do something...
+      return 2, timestamp, record
+      end
+  my_other_lua_script.lua: |
+    ...
+```
+
 ## 3. Customizing Fluentbit for Additional Log Sources
 
 You can extend the logging configuration by extending previous configurations with custom Fluentbit **inputs**, **filters**, or **outputs**. This is especially useful if you want to gather logs from additional sources or apply different processing to specific logs.