docs: improve search for documentation (#6952)

* docs: update search to aio search

* chore: use custom stop word filter for lunr

* docs: applay review suggestions

* docs: remove stop word filtering during search

* docs: improve first search query to search only in title

* docs: remove deprecated import paths from search results

* chore: commit package-lock.json

---------

Co-authored-by: Mladen Jakovljević <jakovljevic.mladen@gmail.com>

(cherry picked from commit 0175187)

docs_app/.gitignore

@@ -46,8 +46,5 @@ protractor-results*.txt
 .DS_Store
 Thumbs.db
 
-# copied dependencies
-src/assets/js/lunr*
-
 assets/images/svgs/*
 !assets/images/svgs/.gitkeep

docs_app/angular.json

@@ -15,6 +15,7 @@
             "index": "src/index.html",
             "main": "src/main.ts",
             "tsConfig": "src/tsconfig.app.json",
+            "webWorkerTsConfig": "tsconfig.worker.json",
             "namedChunks": true,
             "polyfills": "src/polyfills.ts",
             "assets": [