Serve HTTPS only option

Problem/Motivation

There's no option to force use https for the download, edit, and go back urls

Steps to reproduce

Proposed resolution

Add a "Serve over https only" option on the Settings
On the OnlyofficeUrlHelper add a logic to check for the settings if Serve over https only option is ticked, then set https options on the Url class.

Remaining tasks

User interface changes

API changes

Data model changes