Give the service an appropriate domain name.

[obrien-j]

Now that we're in a public beta phase, in accordance with https://www.tbs-sct.gc.ca/pol/doc-eng.aspx?id=24227 , Appendix B, "Domains", we should create a policy compliant domain name and update outbound letters to users.

We're reaching out to acquire zone delegation on *.beta.canada.ca which may serve as a potential option, but can use an IRCC specific domain (cic.gc.ca?) if desired as well.

Note: The service itself will require an appropriate name itself that meets the above policy requirements.