Update Qt5 to 5.15
This is a major upgrade of the Qt libraries , .
* People that use upgrading mechanisms with incomplete dependency handling
(portmaster & Co) should make sure to manually remove the existing Qt
packages to guarantee a safe upgrade. Keep in mind, that Qt does not like if
you have an incomplete upgrade.
* This version of Qt drops support for OpenSSL 1.0 -- this means that there
won't be any binary packages for Qt5 provided by the FreeBSD package builders
for FreeBSD 11.x anymore -- and the same for *all* the ports depending on
net/qt5-network . If you cannot upgrade to a more recent FreeBSD
version (12.x, 13.x), you will need to build Qt5 from ports while switching
to an SSL implementation from ports.(Only the first 15 lines of the commit message are shown above )