feat: Add ability to pass http headers to the soap client

[trzenaro]

• add ability to pass http headers to the soap client
• fix unit test service unavailability

Signed-off-By: Thiago Zenaro trzenaro@gmail.com

This pull request aims to add the ability to pass some http headers to the soap client, since some servers may need to receive some extra headers to work properly. The client already supports adding headers, as shown here.

It also fixes broken unit tests due to unavailability of service http://ws.cdyne.com/emailverify/Emailvernotestemail.asmx

Checklist

• [x] DCO (Developer Certificate of Origin) signed in all commits
• [x] npm test passes on your machine
• [x] New tests added or existing tests modified to cover all changes
• [x] Code conforms with the style guide
• [x] Commit messages are following our guidelines