:zap: perf: several optimizations for improving the performance of the engine (#540)

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

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

Create separate search_result_parser

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

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)