feat: add support to paragon design tokens [wip]

  This PR purpose is to test/demo parago design tokens simliar
  to this one for the profile openedx/frontend-app-profile/pull/764

  it override the following depns as seen in package.json

  - paragon alpha
  - openedx/frontend-build/pull/365
  - openedx/frontend-platform/pull/440
  - openedx/frontend-component-header/pull/351
  - openedx/frontend-component-footer/pull/303

 Conclousion so far:

 - There is an extra library that learning depends on which
  needs to support paragon; `frontend-lib-learning-assistant`
  and also `frontend-lib-special-exams`

 - It would be great to have a gudie or a document to look at,
 while doing the conversion that would **map variable from
 who it was used/named before to the name in design tokens**

 - I was stuck in the end with compliation error, that
 wepack couldn't find `Modal` exported from paragon.

.env.development

@@ -48,3 +48,5 @@ USER_INFO_COOKIE_NAME='edx-user-info'
 SESSION_COOKIE_DOMAIN='localhost'
 CHAT_RESPONSE_URL='http://localhost:18000/api/learning_assistant/v1/course_id'
 PRIVACY_POLICY_URL='http://localhost:18000/privacy'
+APP_ID='learning'
+MFE_CONFIG_API_URL='http://localhost:18000/api/mfe_config/v1'

env.config.example.js

@@ -0,0 +1,22 @@
+const config = {
+    PARAGON_THEME_URLS: {
+      core: {
+        urls: {
+          default: 'https://cdn.jsdelivr.net/npm/@edx/paragon@$paragonVersion/dist/core.min.css',
+          brandOverride: 'https://cdn.jsdelivr.net/npm/@edx/brand-edx.org@$brandVersion/dist/core.min.css',
+        },
+      },
+      variants: {
+        light: {
+          urls: {
+            default: 'https://cdn.jsdelivr.net/npm/@edx/paragon@$paragonVersion/dist/light.min.css',
+            brandOverride: 'https://cdn.jsdelivr.net/npm/@edx/brand-edx.org@$brandVersion/dist/light.min.css',
+          },
+          default: true,
+          dark: false,
+        },
+      },
+    },
+  };
+
+  export default config;