Precompute MSDFs for all ASCII glyphs; after this, we no longer spend any time on MSDF computations when loading or interacting with the example projects.
Also shader precompilation (during build) is now parallel; if you have many cores and an SSD, it's now practically instant.
Closes#5722.
# Important Notes
- The *dynamic-assets* mechanism now used for MSDF data and shaders is versatile, and could be used to pre-seed any other computation-intensive runtime caches.
