Resolves#315154.
New Web UI uses an unfree web theme, and as a result it...
> is allowed for use only within the SFTPGo product and therefore
> cannot be used in derivative works/products without an explicit
> grant from the SFTPGo Team (support@sftpgo.com).
This makes the entire package unfree, which the [SFTPGo license
compliance page][1] supports:
> If you modify SFTPGo's source code and are therefore creating a
> derivative work:
>
> 1. ...
> 2. ...
> 3. You cannot use the UI theme based on KeenThemes because it is
> based on a proprietary theme that we purchased and the WebAdmin and
> WebClient components created using this theme can only be used only
> within SFTPGo and not in derivative works. You must develop and
> maintain your own UI components or adapt the WebAdmin/WebClient
> included in SFTPGo up to version 2.5.6.
@JohnRTitor noted that building from source might not be derivative
work, therefore marking as `unfreeRedistributable`.
[1]: https://sftpgo.com/compliance.html
Co-authored-by: Masum Reza <masumrezarock100@gmail.com>
