Handle new Zint API >= 2.7.0

[gitlost]

Add handling of new Zint API >= 2.7.0 for Zint backend and use latest version (2.12.0) by default (fixes #86 and #160, subsumes PR #164).

• hack "FindLibZint.cmake" to use zint -h to get version; define LIBZINT_VERSION
• add new API handling in Zint in LIBZINT_VERSION >= 20700 define, leaving 2.6.3 handling unchanged
• add some new Zint barcodes and adjust style properties of various other Zint barcodes
• enable check digit handling via Zint option_2
• add horizontal alignment halign argument to Barcode::ahddText(), QtRenderer::drawText() and DrawingPrimitiveText::DrawingPrimitiveText() and use in QtRenderer::drawText() to cater for Zint EAN/UPC left/right text align of outside digits
• guard against QT infinite loop bug in QFontMetricsF when point size < ~0.4 (MIN_POINT_SIZE)

[CapnKernel]

These two patches were exactly what I needed to get glabels-qt to compile in Fedora. Thank you @gitlost!

[fedora-mahdi]

These two patches were exactly what I needed to get glabels-qt to compile in Fedora. Thank you @gitlost!

@CapnKernel

Could you please detail the commands and environment required to compile glabels-qt in Fedora ? Through dnf search glabels or flathub the is and old version (3.4 if I remember correctly)

Thanks for your help.