Adding Multi-Platform Docker Images and Build Pipelines

[justgook]

Resolves #290

there is now 2 Docker files

1. Dockerfile - main file to build SGDK build image
2. deps/gcc.Dockerfile - m68k-gcc dependency - that is build only once, and then is just reused in Dockerfile (takes REALLY long time to build it 3h 49m 35s)

After deps/gcc.Dockerfile is build it will be reused, SGDK image will build each time when there is commit that changes or updates code in repo, and pushed to ghcr.io docker registry as docker pull ghcr.io/Stephane-D/sgdk

EXTRA while was waiting for build to finish added Doxygen doc generation and publishing to gh-pages (need to add permissions to allow GitHub Actions publish Pages it in settings, set Source to GitHub Actions)

[justgook]

looks like need to cleanup some css to make linter happy..

[justgook]

BTW, can some one tell me what command to use to build jar tools, really would like automate (as soon code changes, new jar is created in CI) also those tools building.

(i have JavaFobia, in my 20+ years i somehow avoided to write in Java)

[justgook]

looks like i will splitting all that stuff in two different PR (question about java is still open)

[justgook]

DUPLICATE #293