Make use of all Qt features conditional that are not supported on the
web assembly platform (mainly TLS support and QProcess).
Note that HTTPs is supposed to work nevertheless as long as the certificate
matches (with the usual corss-site scripting limitations).
* Allow to pause all devices on metered network connections (devices will
be automatically resumed when network is no longer metered)
* Allow to stop Syncthing when it was started via the built-in launcher
on metered network connections (it will be automatically started again
when the network connection is no longer metered)
* See https://github.com/Martchus/syncthingtray/issues/231
* Unify code paths for compiling expected SSL errors so in any case the
expected errors are including the error types emitted by the Schannel
backend
* See https://github.com/Martchus/syncthingtray/issues/223
Apparently the default before introducing the request timeout was not 30000
(which is the value of QNetworkRequest::TransferTimeoutConstant). There was
actually no timeout. So let's restore this behavior for now as the main
intention was to make the timeout configurable but not change any defaults.
Martchus