### Summary

`ansible.template.is_template` tries to loop until it determines if the value is indeed a template.  Which means we could loop extremely large strings, that don't even remotely look like templates, before we bail.

However, we could benefit from moving `Templar.is_possibly_template` to the global scope, and testing whether the value after `jinja_env.preprocess` is even possibly a template, before doing more computationally complex validation.

### Issue Type

Feature Idea

### Component Name

lib/ansible/template/__init__.py

### Additional Information

<!--- Paste example playbooks or commands between quotes below -->
```yaml (paste below)

```


### Code of Conduct

- [X] I agree to follow the Ansible Code of Conduct
if self._ansible_plugins_loaded:
            return
        for plugin in self._pluginloader.all():
            try:
                method_map = getattr(plugin, self._method_map_name)
                self._delegatee.update(method_map())
            except Exception as e:
                display.warning("Skipping %s plugin %s as it seems to be invalid: %r" % (self._dirname, to_text(plugin._original_path), e))
                continue
        if self._pluginloader.class_name == 'FilterModule':
            for plugin_name, plugin in self._delegatee.items():
                if self._jinja2_native and plugin_name in C.STRING_TYPE_FILTERS:
                    self._delegatee[plugin_name] = _wrap_native_text(plugin)
                else:
                    self._delegatee[plugin_name] = _unroll_iterator(plugin)
        self._ansible_plugins_loaded = True
    
    
    def __getitem__(self, key):