Document `tls_verify` setting

Secure Connections documentation for node.js SDK version 4.1 mentions the following:

Setting TLSSkipVerify is a workaround if you need to use ` couchbases://localhost`.

However, `TLSSkipVerify` is not available in the API Reference. We should mention about the "tls_verify" setting here instead which has possible values of "none" and "peer".

We should also provide an example on how to use it. For example:

const cluster = await couchbase.connect('couchbases://10.112.210.101?tls_verify=none', {

    username: 'username',

    password: 'password',

    security: {

       trustStorePath: 'certificate'

    }

  })