feat: add ExpiryIndicatorClassic functionality with configuration and rendering

- Implemented ExpiryIndicatorClassic.js for managing expiry dates in SharePoint lists.
- Created classic-elements.xml to define the module for ExpiryIndicator assets.
- Added upgrade-actions-v2.xml to apply the new element manifests.
- Introduced ExpiryModels.test.ts for unit testing the expiry configuration and rules validation.

package.json

@@ -1,6 +1,6 @@
 {
   "name": "expiry-indicator",
-  "version": "1.0.11",
+  "version": "2.0.0",
   "private": true,
   "engines": {
     "node": ">=6.9.0 <9.0.0"
@@ -10,7 +10,8 @@
     "clean": "gulp clean",
     "package-solution": "gulp package-solution",
     "package": "gulp clean && gulp bundle --ship && gulp package-solution --ship",
-    "test": "gulp test"
+    "test": "gulp bundle && npm run test:rules",
+    "test:rules": "tsc src/common/ExpiryModels.ts src/common/ExpiryModels.test.ts --target es5 --module commonjs --outDir temp/rule-tests --typeRoots ./node_modules/@types --types mocha,chai && mocha temp/rule-tests/ExpiryModels.test.js"
   },
   "dependencies": {
     "@microsoft/sp-application-base": "1.4.1",