Split up the RequestALetterController into separate controllers for sending and resending

[jmhooper]

This changes reduces some confusion in the IdV flow. It will need to be made in 3 parts:

1. Adding the new routes with functionality
2. Directing to the new routes
3. Tearing down the old routes

This change is here to make sure it all works together while I do the above in separate commits

[jmhooper]

I meant to open this as a draft. It is not intended to be merged. I'll be opening PRs for the component parts and asking for a review on those once I get this green.

[zachmargolis]

we have a shared/_address.html partial, looks like we could use it here if we want?

Suggested change

	<%= @applicant[:address1] %>
	<br />
	<% if @applicant[:address2] %>
	<%= @applicant[:address2] %>
	<br />
	<% end %>
	<%= @applicant[:city] %>, <%= @applicant[:state] %> <%= @applicant[:zipcode] %>
	<br />
	<%= render partial: 'shared/address', address: @applicant %>
	<br />

or maybe if we want to not pass the whole applicant

Suggested change

	<%= @applicant[:address1] %>
	<br />
	<% if @applicant[:address2] %>
	<%= @applicant[:address2] %>
	<br />
	<% end %>
	<%= @applicant[:city] %>, <%= @applicant[:state] %> <%= @applicant[:zipcode] %>
	<br />
	<%= render partial: 'shared/address', address: @applicant.slice(:address1, :address2, :city, :state, :zipcode) %>
	<br />

[jmhooper]

Nice, yeah that looks like a good change

[jmhooper]

I have split these changes up across the following PRs:

• Add a Idv::ByMail::ResendLetterController and associated routes #10864
• Begin using the new ResendLetterController #10865
• Remove the resend functionality from the RequestLetterController #10866