Use venv for Python dependencies (macOS)

Create a series of scripts to set up and manage a Python virtual
environment that can be used to build (and test) Drake. Remove Python
packages from macOS setup. Add dependencies to the virtual environment
as needed.

.gitignore

@@ -28,3 +28,4 @@
 
 # User-specified configuration
 /user.bazelrc
+/requirements.txt

bindings/pydrake/BUILD.bazel

@@ -48,6 +48,7 @@ drake_py_library(
     ],
     deps = [
         "//bindings/pydrake/common:_init_py",
+        "@venv",
     ],
 )
 
@@ -399,6 +400,7 @@ drake_py_binary(
         ":all_py",
         "@mypy_internal//:mypy",
         "@stable_baselines3_internal//:stable_baselines3",
+        "@venv",
     ],
 )
 

requirements-base.in

@@ -0,0 +1,26 @@
+# PyPI packages to make available as Drake's bazel `@venv` repository.
+
+# WARNING: If you change this file, then it is up to you to regenerate
+# the "locked" requirements.txt file via:
+#
+#     tools/workspace/venv/upgrade
+
+# Packages that we are happy to take the most recent version any time we
+# update requirements.  The versions of these packages are "locked" in the
+# requirements.txt file and change any time it updates.  This should be
+# the overwhelming majority of our requirements.
+
+ipython
+ipywidgets
+matplotlib
+notebook
+numpy < 2.1
+Pillow
+pydot
+PyYAML
+
+# The following are constrained or pinned version of packages.
+
+# Keep `black` and `isort` fixed until we want to explicitly update.
+black == 22.10.0
+isort == 5.1.3

requirements-test.in

@@ -0,0 +1,18 @@
+# PyPI packages to make available as Drake's bazel `@venv` repository.
+
+# WARNING: If you change this file, then it is up to you to regenerate
+# the "locked" requirements.txt file via:
+#
+#     tools/workspace/venv/upgrade
+
+# Packages that we are happy to take the most recent version any time we
+# update requirements.  The versions of these packages are "locked" in the
+# requirements.txt file and change any time it updates.  This should be
+# the overwhelming majority of our requirements.
+
+flask
+six
+u-msgpack-python
+websockets
+
+# The following are constrained or pinned version of packages.