Document page naming best practice

Document page naming best practices for authors in https://www.hlx.live/docs/authoring

From @ kptdobe:

> In gdrive / sharepoint, it is recommended to use filenames in lowercase, without spaces (dashes instead) and with only latin characters. Dynamic Quotes should become dynamic-quotes. While both works, the recommended version is better to educate authors to maintain clean urls and have a. clear mapping between url and filename.
> If you name you document This Is A crazy Name with àccent, spaces & extra fancy.?-things .docx there is no way you can guess the url or the filename from the url
>