Support Qt 5.15 and msvc2019

Added

• Support installation of Qt version for msvc2019
• Add knowledge of components combination on 5.14 and 5.15

Changed

• Show detailed diagnose message when error happend.
• CI test with Qt 5.14.2 and 5.15.0
• CI test with installed mingw tools compiler.
• Depends on py7zr v0.7.0b2 and later.

Fixed

• Tools: Fix mingw installation failure.
• Fix --outputdir behavior about path separator on windows