Add `flake.nix`??

[81reap]

Continuing this thread in an issue so that we can merge the PR.

Nix has different tools for different situations. In this case, a development shell. It acts similar to a makefile and is completely opt in and fixes the lack of unified build command.

If we choose to opt the CI into using the flake then we can ::

1. Cache the build artifacts into Github Actions Cache
2. Replace the Hurl archive scripts

   SQLPage/.github/workflows/ci.yml

   Lines 425 to 452 in f07c27f

   	- name: Restore Hurl archive
   	id: hurl-cache
   	uses: actions/cache@v6
   	with:
   	path: .cache/hurl
   	key: hurl-${{ runner.os }}-x86_64-unknown-linux-gnu-${{ env.HURL_VERSION }}
   	- name: Download Hurl archive
   	if: steps.hurl-cache.outputs.cache-hit != 'true'
   	run: |
   	set -euo pipefail
   	archive="hurl-${HURL_VERSION}-x86_64-unknown-linux-gnu.tar.gz"
   	base_url="https://github.com/Orange-OpenSource/hurl/releases/download/${HURL_VERSION}"
   	mkdir -p .cache/hurl
   	curl --fail --location --retry 5 --retry-delay 2 --output ".cache/hurl/${archive}" "${base_url}/${archive}"
   	curl --fail --location --retry 5 --retry-delay 2 --output ".cache/hurl/${archive}.sha256" "${base_url}/${archive}.sha256"
   	(
   	cd .cache/hurl
   	expected_sha="$(tr -d '[:space:]' < "${archive}.sha256")"
   	actual_sha="$(sha256sum "$archive" | cut -d ' ' -f 1)"
   	test "$expected_sha" = "$actual_sha"
   	)
   	- name: Upload Hurl archive
   	uses: actions/upload-artifact@v7
   	with:
   	name: hurl-${{ env.HURL_VERSION }}-x86_64-unknown-linux-gnu
   	path: .cache/hurl/*
   	if-no-files-found: error
   	retention-days: 1

3. Replace the Playwright scripts

   SQLPage/.github/workflows/ci.yml

   Lines 212 to 214 in f07c27f

   	- uses: ./.github/actions/install-frontend-dependencies
   	- run: sudo apt-get update && sudo apt-get install -y unixodbc-dev
   	- run: npx playwright install --with-deps --only-shell chromium

4. Replace the OBDC installer scripts

   SQLPage/.github/workflows/ci.yml

   Lines 131 to 144 in f07c27f

   	- name: Install PostgreSQL ODBC driver
   	if: matrix.setup_odbc
   	run: sudo apt-get install -y odbc-postgresql
   	- name: Install Oracle ODBC driver
   	if: matrix.database == 'oracle'
   	run: |
   	sudo apt-get install -y alien libaio1t64 libodbcinst2 unixodbc
   	sudo rpm --import https://yum.oracle.com/RPM-GPG-KEY-oracle-ol8
   	wget https://yum.oracle.com/repo/OracleLinux/OL8/oracle/instantclient21/x86_64/getPackage/oracle-instantclient-{basic,odbc}-21.21.0.0.0-1.el8.x86_64.rpm
   	sudo alien -i oracle-instantclient-basic-21.21.0.0.0-1.el8.x86_64.rpm
   	sudo alien -i oracle-instantclient-odbc-21.21.0.0.0-1.el8.x86_64.rpm
   	sudo ln -s /usr/lib/x86_64-linux-gnu/libaio.so.1t64 /usr/lib/libaio.so.1
   	sudo /usr/lib/oracle/21/client64/bin/odbc_update_ini.sh / /usr/lib/oracle/21/client64/lib
   	echo "LD_LIBRARY_PATH=/usr/lib/oracle/21/client64/lib:$LD_LIBRARY_PATH" >> "$GITHUB_ENV"

5. Replace the lint with a unified command

   SQLPage/.github/workflows/ci.yml

   Lines 47 to 48 in f07c27f

   	- run: cargo fmt --all -- --check
   	- run: cargo clippy --all-targets --all-features -- -D warnings

[81reap]

lol @lovasoa ironically the current stack of CI fixes ran into unrelated download issues as an example of what this could fix https://github.com/sqlpage/SQLPage/actions/runs/35961180296/job/107510746645?pr=1486