CORS and preflight requests

<!-- Be help prevent duplicates by searching existing issues first 🙂 Here are a few helpful tips, depending on what type of issue you are creating: [Bug] – Provide a detailed description, as well as steps for anyone to reproduce the issue [Feature Request] – Provide concrete use cases to go along with these requests [Question] – Ask whatever you want! --> • Insomnia Version: 5.12.4 • Operating System: Windows 10 x64 Details Currently, Insomnia ignores any possible CORS issues, and always sends the request as is. It would be nice to have the option to enable a strict CORS mode, where Insomnia would mirror the current behavior of browsers, by following the CORS spec and performing the following steps: 1) Check if the request requires a preflight request. 2) If yes, send a preflight request first. 3) If the server responds with an error, display that and abort the request. 4) If server responds with a preflight response, check the original r…