Qt 5.9.3 support

[ImpressiveDev]

Hi @osechet. Do you plan on doing a release for Qt 5.9.3 (on bintray.com)?

[ImpressiveDev]

Hi @osechet. I forked the "testing/5.8.0" to provide a base for the 5.9.3 version.
https://github.com/ImpressiveDev/conan-qt/tree/testing/5.9.3