Finish pinning system rewrite (#8934)

* add oldest pyproject.toml file that works

* make single oldest_constraints.txt file

* remove unused merge_requirements.py

* remove unused import

* make conditional right

* simplify pip_install.py

* fix typo

* bump min dns-lexicon dependency

* fix zope import warning

* pin back wheel

* refactor pinning script

* Add oldest script.

* add pip comment

* add pipstrap extra

* simplify pinning scripts

* remove pipstrap extra

* update contributing

* Add design doc

* Update tools/pinning/DESIGN.md

Co-authored-by: ohemorange <erica@eff.org>

* Update tools/pinning/DESIGN.md

Co-authored-by: ohemorange <erica@eff.org>

* Update tools/pinning/DESIGN.md

Co-authored-by: ohemorange <erica@eff.org>

* Update tools/pinning/DESIGN.md

Co-authored-by: ohemorange <erica@eff.org>

* rename normal to current

* no dummies

* script improvements

* mention need to update setup.py

* try and clarify poetry behavior

* tweak section title

Co-authored-by: ohemorange <erica@eff.org>

tools/pinning/common/export-pinned-dependencies.sh

@@ -0,0 +1,44 @@
+#!/bin/bash
+# This script accepts a directory containing a pyproject.toml file configured
+# for use with poetry and generates and prints the pinned dependencies of that
+# file. Any dependencies on acme or those referencing certbot will be removed
+# from the output. The exported requirements are printed to stdout.
+#
+# For example, if a directory containing a pyproject.toml file for poetry is at
+# ../current, you could activate Certbot's developer environment and then run a
+# command like the following to generate requirements.txt for that environment:
+#   ./export-pinned-dependencies.sh ../current > requirements.txt
+set -euo pipefail
+
+# If this script wasn't given a command line argument, print usage and exit.
+if [ -z ${1+x} ]; then
+    echo "Usage:" >&2
+    echo "$0 PYPROJECT_TOML_DIRECTORY" >&2
+    exit 1
+fi
+
+REPO_ROOT="$(git rev-parse --show-toplevel)"
+WORK_DIR="$1"
+
+if ! command -v poetry >/dev/null || [ $(poetry --version | grep -oE '[0-9]+\.[0-9]+' | sed 's/\.//') -lt 12 ]; then
+    echo "Please install poetry 1.2+." >&2
+    echo "You may need to recreate Certbot's virtual environment and activate it." >&2
+    exit 1
+fi
+
+# Old eggs can cause outdated dependency information to be used by poetry so we
+# delete them before generating the lock file. See
+# https://github.com/python-poetry/poetry/issues/4103 for more info.
+rm -rf ${REPO_ROOT}/*.egg-info
+
+cd "${WORK_DIR}"
+
+if [ -f poetry.lock ]; then
+    rm poetry.lock
+fi
+
+poetry lock >&2
+trap 'rm poetry.lock' EXIT
+
+# We need to remove local packages from the output.
+poetry export --without-hashes | sed '/^acme @/d; /certbot/d;'