Digger Remastered runtime built for PLAYCHIVE

Upstream repository: https://github.com/sobomax/digger
Pinned revision: e85cab1164f0304b3e66f371a5997d83f7a0090a
Upstream project: https://www.digger.org/

The Digger Remastered upstream README documents the source's historical mixed
license notices, including Public Domain, Beer-Ware, 2-clause BSD and GPL-2.0.
The original README is included at DIGGER-UPSTREAM-NOTICES.txt. Corresponding
source is available from the repository above; PLAYCHIVE's build recipe is
scripts/build-digger-web.sh.

Packaging changes: Digger's upstream  target is used unmodified for
game code. The Google webfont import and external GitHub link in its HTML shell
were removed. The game JavaScript, WASM and build-info assets are all local.