Rename email reminders task to include first

[cintamani]

This renames the Email reminders to include first so that we can distinguish between the first and second email reminders later on.

Open to suggestion. I am not super super happy about this naming 🤔

[Cruikshanks]

I've spoken to the team in the office today. Currently it looks like the content for the first and second email is the same.

However they feel there is scope for having different content in the second email.

So the 2 service objects will have 2 different params

• the period of time to filter expiring registrations by
• the email to actually send

So to me that leaves 2 options

• go with what you have done (and I cannot think of a better name at this time 😁 )
• pass in these values to a generic RenewalReminderService from the rake task

I like to keep rake tasks as simple as possible, so to avoid looking at env vars and the like my preference would be we end up with a FirstRenewalReminderService, SecondRenewalReminderService, and a BaseRenewalReminderService possibly in a app/services/reminder namespace.

On that basis I'm happy with the changes here.

[cintamani]

Thanks @Cruikshanks :D Me and Iris discussed this already #245 (comment) :) we agree with the 2 separate services approach but I have left this change out of the other main PRs :)