Resource file like css and json should skip rendering by default

[D-Sketon]

Check List

Please check followings before submitting a new feature request.

• [x] I have already read Docs page
• [x] I have already searched existing issues

Feature Request

Resource file like css and json should skip rendering by default. In this case, users don't need to add file path to skip_render in _config.yml

Others

if this feature can be realized, the issue #4976 may be solved

[renbaoshuo]

I don't think it should be set as the default option, some existing plugins (like https://github.com/hexojs/hexo-clean-css) depend on this behavior.

[renbaoshuo]

Maybe we can consider setting disableNunjucks to true for css files.

[stevenjoezhang]

See also https://github.com/hexojs/hexo/issues/4468