Add support file.serialize in linux:system:file

Ensure presence of file to be serialized through one of the serializer modules
(see: https://docs.saltstack.com/en/latest/ref/serializers/all/index.html):

README.rst

@@ -389,6 +389,20 @@ Ensure presence of file by specifying it's contents:
           /tmp/test.txt:
             contents_grains: motd
 
+Ensure presence of file to be serialized through one of the serializer modules
+(see: https://docs.saltstack.com/en/latest/ref/serializers/all/index.html):
+
+.. code-block:: yaml
+
+    linux:
+      system:
+        file:
+          /tmp/test.json:
+            serialize: json
+            contents:
+              foo: 1
+              bar: 'bar'
+
 Kernel
 ~~~~~~
 

linux/system/file.sls

@@ -4,12 +4,16 @@
 {%- for file_name, file in system.file.items() %}
 
 linux_file_{{ file_name }}:
+{%- if file.serialize is defined %}
+  file.serialize:
+    - formatter: {{ file.serialize }}
+  {%- if file.contents is defined  %}
+    - dataset: {{ file.contents|yaml }}
+  {%- elif file.contents_pillar is defined %}
+    - dataset_pillar: {{ file.contents_pillar }}
+  {%- endif %}
+{%- else %}
   file.managed:
-    {%- if file.name is defined %}
-    - name: {{ file.name }}
-    {%- else %}
-    - name: {{ file_name }}
-    {%- endif %}
     {%- if file.source is defined %}
     - source: {{ file.source }}
     {%- if file.hash is defined %}
@@ -24,6 +28,12 @@ linux_file_{{ file_name }}:
     {%- elif file.contents_grains is defined %}
     - contents_grains: {{ file.contents_grains }}
     {%- endif %}
+{%- endif %}
+    {%- if file.name is defined %}
+    - name: {{ file.name }}
+    {%- else %}
+    - name: {{ file_name }}
+    {%- endif %}
     - makedirs: {{ file.get('makedirs', 'True') }}
     - user: {{ file.get('user', 'root') }}
     - group: {{ file.get('group', 'root') }}