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##### SUMMARY
Add comment_start_string and comment_end_string to template plugin.

##### ISSUE TYPE
- Feature Idea

##### COMPONENT NAME
template

##### ADDITIONAL INFORMATION
In some situation, we need to change comment behavior of template plugin, for an example macros in Zabbix is like {#MACRO}.

<!--- Paste example playbooks or commands between quotes below -->
```yaml
- name: Render a template with "comment_start_string" set to [#
  template:
    src: template.xml.j2
    dest: template.xml
    comment_start_string: "[#"
    comment_end_string: "#]"
```

<!--- HINT: You can also paste gist.github.com links for larger files -->

else:
                try:
                    source = self._find_needle('templates', source)
                except AnsibleError as e:
                    raise AnsibleActionFail(to_text(e))
            mode = self._task.args.get('mode', None)
            if mode == 'preserve':
                mode = '0%03o' % stat.S_IMODE(os.stat(source).st_mode)
            
            try:
                tmp_source = self._loader.get_real_file(source)
            except AnsibleFileNotFound as e:
                raise AnsibleActionFail("could not find src=%s, %s" % (source, to_text(e)))
            b_tmp_source = to_bytes(tmp_source, errors='surrogate_or_strict')
            
            try:
                with open(b_tmp_source, 'rb') as f:
                    try:
                        template_data = to_text(f.read(), errors='surrogate_or_strict')
                    except UnicodeError:
                        raise AnsibleActionFail("Template source files must be utf-8 encoded")
                
                searchpath = task_vars.get('ansible_search_path', [])
                searchpath.extend([self._loader._basedir, os.path.dirname(source)])
                
                
                newsearchpath = []
                for p in searchpath:
                    newsearchpath.append(os.path.join(p, 'templates'))
                    newsearchpath.append(p)