feat(next-drupal): add NextDrupal and NextDrupalBase class definitions

The DrupalClient class has been renamed to NextDrupalPages and has been
refactored to inherit from the NextDrupalBase (base class) and NextDrupal
(JsonAPI/App Router class). NextDrupalPages class contains the methods that are
only needed to support Next.js' Pages Router. NextDrupalPages is also available
as "DrupalClient" for backwards-compatibility.

The getPathFromContext() method has been replaced with the
constructPathFromSegment() method for App Router usages.

Issue #665

packages/next-drupal/jest.config.cjs

@@ -14,6 +14,8 @@ module.exports = {
     ],
   },
   testLocationInResults: true,
+  // TODO: Remove prettierPath after Jest v30 release. See https://github.com/jestjs/jest/issues/14305
+  prettierPath: null,
   coverageProvider: "v8",
   collectCoverage: true,
   collectCoverageFrom: ["./src/**"],