Contains contributions from Waad, Alja and Matevz. Squashed to avoid adding of
extra files in the repo (some committed by mistake) and to avoid numerous commits.

* Waad: initial implementation & tuning.
* Alja: integration with REve.
* Matevz: final cleanup, loading of fonts & font metrics. Mac and Windows fixes.

Full set of initial development commits is available from:
https://github.com/alja/root/tree/waa-master-2024

Commits to get things working on Mac/Windows and libAfterImage/libpng:
https://github.com/alja/root/tree/waad-revetext-overlay-master-6.33-rb1-final

Related PR in RenderCore: https://github.com/UL-FRI-LGM/RenderCore/pull/20

Demo: tutorials/eve7/texts.C

Update RenderCore version to 1.5.

Location of SDF font and metrics files:

When REveText::AssertSdfFont() is called for the first time it chooses a writable
location in eiter $ROOTSYS/ui5/eve7/sdf-fonts or a ./sdf-fonts in the current
directory.
Alternatively REveText::SetSdfFontDir() can be called beforehand to manually
specify the desired location.