build: npm run compile-sass

TODO update ADR
TODO themes env var
TODO make compile-requirements
TODO testing
TODO comment in compile_sass.py a la "this could be a shell script"

TODO add details from PR description

Part of: TODO

package.json

@@ -3,8 +3,12 @@
   "version": "0.1.0",
   "repository": "https://github.com/openedx/edx-platform",
   "scripts": {
+    "build": "npm run webpack && npm run compile-sass",
+    "build-dev": "npm run webpack-dev && npm run compile-sass-dev",
     "webpack": "NODE_ENV=production webpack --progress --config=${WEBPACK_CONFIG_PATH:-webpack.prod.config.js}",
-    "webpack-dev": "NODE_ENV=development webpack --progress --config=${WEBPACK_CONFIG_PATH:-webpack.dev.config.js}"
+    "webpack-dev": "NODE_ENV=development webpack --progress --config=${WEBPACK_CONFIG_PATH:-webpack.dev.config.js}",
+    "compile-sass": "compile_sass.py",
+    "compile-sass-dev": "NODE_ENV=development compile_sass.py"
   },
   "dependencies": {
     "@babel/core": "7.19.0",

requirements/constraints.txt

@@ -109,3 +109,9 @@ drf-yasg<1.21.6
 
 # Adding pin to avoid any major upgrade
 djangorestframework<3.15.0
+
+# Our legacy Sass code is incompatible with anything except this ancient libsass version.
+# Here is a ticket to upgrade, but it's of debatable importance given that we are rapidly moving
+# away from legacy LMS/CMS frontends:
+# https://github.com/openedx/edx-platform/issues/31616
+libsass==0.10.0

requirements/edx/paver.in

@@ -12,7 +12,6 @@
 
 edx-opaque-keys                     # Create and introspect course and xblock identities
 lazy                                # Lazily-evaluated attributes for Python objects
-libsass==0.10.0                     # Python bindings for the LibSass CSS compiler
 markupsafe                          # XML/HTML/XHTML Markup safe strings
 mock                                # Stub out code with mock objects and make assertions about how they have been used
 path                                # Easier manipulation of filesystem paths

requirements/edx/paver.txt

@@ -16,8 +16,6 @@ idna==3.4
     # via requests
 lazy==1.5
     # via -r requirements/edx/paver.in
-libsass==0.10.0
-    # via -r requirements/edx/paver.in
 markupsafe==2.1.3
     # via -r requirements/edx/paver.in
 mock==5.0.2
@@ -41,7 +39,6 @@ requests==2.31.0
     # via -r requirements/edx/paver.in
 six==1.16.0
     # via
-    #   libsass
     #   paver
     #   python-memcached
 stevedore==5.1.0

requirements/edx/sass.in

@@ -0,0 +1,4 @@
+-c constraints.txt
+
+click
+libsass