[JS]: Adding express-validator support

[GeekMasher]

This PR adds support for express-validator, a middleware for Express.js that provides a way to validate incoming requests.

This should reduce the false positives a number of users are seeing

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[asgerf]

The test case file seems to be empty?

[asgerf]

The test output needs to be regenerated, otherwise looks good.

An interesting aspect of this library is that validators like isEmail() never actually reject the request; it's up to the user to call validationErrors and reject the request if there are any errors. The best is probably to treat them as sanitisers like you've done here, and then (in another PR) we could add a query to flag up cases where such validators are being without an appropriate check for validation errors.

[GeekMasher]

I will fix up the PR today and hopefully get it out the door.

On the subject of the isEmail, do you want me to remove it, leave as is, or add support for the validation guard? I wasn't sure how I could add the validator guard clause so I left it out.

[asgerf]

Just leave it in.

[GeekMasher]

I've updated the tests but I would like to add more testing before merging