refactor: changed Cookie to use Cow to facilitate using references when building

change: revert Cookie Strings back to &str

refactor: moved settings parsing out of results

✨ `Bing` for the search engine (#473) (#473)

✨ feat(engine): `mojeek` for the search engine (#464)

Merge branch 'rolling' into FEAT/424_reduce-animations-effects-support-for-the-themes

✨ feat: add a new field `animation` to the struct `style` (#424)

✨ `LibreX` for the search engine (#429)

✨ feat(engine): provide startpage search engine (#314)

Merge branch 'rolling' into PERF/384_optimize-the-performance-of-fetching-results-in-the-websurfx-search-engine-backend

⚡️ perf: rewrite the code by using a constant storing a prebuilt client globally for each thread (#384)

⚰️ chore: remove the serialize & deserialize traits on the struct (#302)

♻️ refactor: remove the code to add the `query` & `style` in the `SearchResults` struct & also remove the associated fields from the struct (#302)

✨ `Brave` for the search engine (#335)

Rename the error to NoSuchEngineFound and add the name of missing engine to it

Refactor the search result parsing

Create separate search_result_parser

Merge branch 'rolling' into feat-inform-user-when-no-engines-are-selected

✨ feat: add new check value for no engine selected (#227)

✨ feat: add the safe search field in the `Cookie` struct (#210)

✨ feat: implement code to pass safe search option in the json results (#210)

🛠️ fix: make the redis_url option only available on `redis-cache` feature (#244)

Instead of caching jsons, we can cache the original structure

Merge branch 'rolling' into reorganize-code-and-restructure-the-codebase

⚙️ refactor: reorganize code & restructure codebase for better maintainability (#207)