Add the Premium Mail Settings service

[dedoussis]

Proposed change

Introducing support for the Hide My Email feature of the Premium Mail Settings service.

Type of change

• [ ] Dependency upgrade
• [ ] Bugfix (non-breaking change which fixes an issue)
• [x] New service (thank you!)
• [ ] New feature (which adds functionality to an existing service)
• [ ] Breaking change (fix/feature causing existing functionality to break)
• [ ] Code quality improvements to existing code or addition of tests
• [ ] Documentation or code sample

Example of code:

api = PyiCloudService(apple_id="[email protected]", password="REDACTED")

print(f"All HMEs: {', '.join([hme.hme for hme in api.premiummailsettings.hme_emails])}")

new_hme = api.premiummailsettings.generate_hme()
print(f"Generated new HME: {new_hme}")

label = input("Enter label: ")
api.premiummailsettings.reserve_hme(hme=new_hme, label=label, note="Generated from pyicloud")

print(f"All HMEs: {', '.join([hme.hme for hme in api.premiummailsettings.hme_emails])}")

Additional information

• This PR fixes or closes issue: fixes #
• This PR is related to issue:

Checklist

• [x] The code change is tested and works locally.
• [x] Local tests pass. Your PR cannot be merged unless tests pass
• [x] There is no commented out code in this PR.
• [x] Tests have been added to verify that the new code works.

If user exposed functionality or configuration variables are added/changed:

• [ ] Documentation added/updated to README