Change contactsdb to marketing api

[murich]

Issue Summary

Contactsdb API considered to be legacy and doesn't work anymore, as per communication with support. Contactsdb methods should be replaced with marketing methods

Steps to Reproduce

1. Try to make any action using contactsdb with full permissioned API key
2. Receive 403
3. Contact Sendgrid support to learn that contactsdb is deprecated

Technical details:

• php-http-client Version: master (latest commit: [db6d34e])
• PHP Version: 7.2