Document the limitation of opening `.url` file in linux and its workaround

[saw-jan]

Desktop client can sync files with .url extension (see https://fileinfo.com/extension/url). In windows, these .url file opens in respective application but linux lacks this feature (not sure about MacOS).

From owncloud/ocis#7940 (comment)

Ubuntu22.04 (desktop-client 5.2.0):

• .url files get synced
• no application to open it

Please open client docs issue. We should document this Ubuntu limitation and possible workarounds.

Workaround: https://devio.wordpress.com/2020/03/22/opening-url-files-in-ubuntu/

[michaelstingl]

FAQ page maybe…