docs: Add initial sphinx docs skeleton #1016

Job	Run time
build-vegafusion-python-linux-arm64	16m 23s
build-vegafusion-python-osx-64	29m 56s
build-vegafusion-python-linux-64	15m 14s
build-vegafusion-python-osx-arm64	22m 45s
build-vegafusion-server-linux-64	16m 54s
build-vegafusion-python-win-64	42m 14s
build-vegafusion-server-linux-arm64	14m 43s
build-vegafusion-server-osx-64	41m 54s
build-vegafusion-server-osx-arm64	22m 48s
build-vegafusion-server-win-64	39m 8s
check-rust	8m 3s
build-vegafusion-wasm	11m 19s
check-vegafusion-python	10m 48s
test-rust (ubuntu-20.04)	23m 24s
test-rust (windows-2022)	45m 52s
test-rust (macos-14)	27m 24s
test-vegafusion-python-linux-64	25m 21s
test-vegafusion-python-osx-arm64	1m 0s
test-vegafusion-python-win-64	1m 53s
	6h 57m 3s

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