Execute release export on virtual machine instead of Coin master

In the current system the release exporter is run on Coin master machine and that opens a bag of worms:

• Logging is not linear and it creates a lot of spam in Coin logs that does not belong there
• We cannot see the release exporter state on web interface
• The garbage collection of temporary files that release exporter creates, does not work properly and exposes us to critical bugs: https://bugreports.qt.io/browse/QTQAINFRA-1551
• Debugging of release exporter is difficult
• Consumes vmbuilder cpu and memory

Implementing the release export as a task instead of process, will allow also displaying it on the Coin WebUI integrations -tab. This would allow people to see when the packages are created without needing to parse through coin logs.