apache2: Allow downloads in modern browsers
Closes: #2002 (closed) and couple of other minor changes.
Entire FreedomBox UI is served within a sandbox that is originally meant for cross-site iframes.
A newly introduced flag allow-downloads is required to trigger downloads. Two instances where this is used in FreedomBox is openvpn profiled download and backup download. Firefox 81 and Chrome 83 implement this flag.
Add 'allow-downloads' to sandbox directives to fix this.
References:
- https://github.com/whatwg/html/pull/4293
- https://developer.mozilla.org/en-US/docs/Web/HTML/Element/iframe
- https://bugzilla.mozilla.org/show_bug.cgi?id=1558394
- https://www.chromestatus.com/feature/5706745674465280
Tests:
- Check that OpenVPN profile can be downloaded.
- Check that backups can be downloaded.
- Check on Firefox 78 and Chromium 83.