Allow users to opt out of literal comma "," query parameters parsing

[mouhannad-sh]

Fixes #202 by adding a new optional option parseCommaSeparatedQueryParams to opt-out from parsing multi-value query params with api gateway v2.0 format.

Additionally fixes a bug where the lambda incoming event argument was manipulated during the parsing. This may cause confusion for users attempting to log the original lambda argument when using request.awsLambda.event.queryStringParameters

Checklist

• [x] run npm run test and npm run benchmark
• [x] tests and/or benchmarks are included
• [x] documentation is changed or added
• [x] commit message and code follows the Developer's Certification of Origin and the Code of conduct

[adrai]

Can you extend the readme accordingly?

[mouhannad-sh]

Updated the readme, thanks !

[adrai]

included in v4.1.0 thank you for your contribution