Add openssl to example configure, macOS and Android

See change 

https://codereview.qt-project.org/c/qtqa/tqtc-qt-rta/+/647401

Check if same update can be done to 6.8 and 6.5.

Change adds -DOPENSSL_ROOT_DIR=$OPENSSL_DIR or -DOPENSSL_ROOT_DIR=$OPENSSL_ANDROID_HOME_DEFAULT to the Qt example configure options. This enables compiling grpc examples on macOS and Android (except on Windows) and they can be removed from the exclude_examples list.

Check that all platforms have the env variable available (linux, macOS, Win), the enviroment variable in any jenkins log.

Note, it's added to Android Windows even the grpc examples are still in exclude list, there is another issue to solve, but it's added there also.