[Substrait] Write README for Substrait dialect. #1535

	name: Database Iterators Standalone

	on:
	push:
	branches:
	- main
	pull_request:
	branches:
	- main
	workflow_dispatch:

	jobs:
	build:
	name: Build and Test
	runs-on: ubuntu-22.04
	env:
	LLVM_SYMBOLIZER_PATH: /usr/lib/llvm-14/bin/llvm-symbolizer
	steps:
	- name: Set up Python
	uses: actions/setup-python@13ae5bb136fac2878aff31522b9efb785519f984 # v4.3.0
	with:
	python-version: 3.11

	- name: Checkout project
	uses: actions/checkout@v3
	with:
	path: sandbox

	- name: Install Ninja
	uses: llvm/actions/install-ninja@6a57890d0e3f9f35dfc72e7e48bc5e1e527cdd6c # Jan 17

	- name: Install doxygen
	run: \|
	sudo apt-get install -y doxygen graphviz

	- name: Define build dir
	run: \|
	echo "DATABASE_ITERATORS_STANDALONE_BUILD_DIR=${GITHUB_WORKSPACE}/sandbox/examples/database-iterators-standalone/build" >> $GITHUB_ENV

	- name: Setup CMake
	run: \|
	mkdir ${DATABASE_ITERATORS_STANDALONE_BUILD_DIR}
	cd ${DATABASE_ITERATORS_STANDALONE_BUILD_DIR}
	cmake -G Ninja ..

	- name: Build
	run: \|
	cd ${DATABASE_ITERATORS_STANDALONE_BUILD_DIR}
	ninja
	ninja DatabaseIteratorsDocs

	- name: Test
	run: \|
	cd ${DATABASE_ITERATORS_STANDALONE_BUILD_DIR}
	ninja test

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