This drags in dsnlexer.h to everything that uses EMBEDDED_FILES, but the
parser is actually only used in two files. It's not the only thing to
drag it in, though.
Currently, touching dsnlexer.h rebuilds nearly 800 files, when it
actually is needed by about 50 at most.
SHA256 is fine for one-offs but for large libraries where we might be
running the hash on hundreds of files, the speed difference is
appreciable. We don't require crytographic hashing, just a check that
the original file hasn't been corrupted so Murmur3 satisfies our basic
requirement.
Schematics, symbols, boards and footprints all get the ability to store
files inside their file structures. File lookups now have a
kicad-embed:// URI to allow various parts of KiCad to refer to files
stored in this manner.
kicad-embed://datasheet.pdf references the file named "datasheet.pdf"
embedded in the document. Embeds are allowed in schematics, boards,
symbols and footprints. Currently supported embeddings are Datasheets,
3D Models and drawingsheets
Fixes https://gitlab.com/kicad/code/kicad/-/issues/6918
Fixes https://gitlab.com/kicad/code/kicad/-/issues/2376
Fixes https://gitlab.com/kicad/code/kicad/-/issues/17827
