Add option for FOSS contribution payments (#730)

* First commit

* Use subscription flow for monetary contributions

* Removed only part of the SPAN

* Localize Stripe payments message

* More localization of contribution strings

* Missed two billing to payment changes

* Fix tests

* Localization of "Open Demo" strings

* Fix grammar error

* Update for consistency

* Localize CTA

* More localilzation strings

app/views/subscriptions/_plan_choice.html.erb

@@ -1,6 +1,6 @@
 <%# locals: (plan:, form:, checked: false) %>
 
-<% price = plan == "annual" ? 90 : 9 %>
+<% price = plan == "annual" ? 25 : 2.50 %>
 <% frequency = plan == "annual" ? "/year" : "/month" %>
 
 <div class="relative">
@@ -14,17 +14,13 @@
 
     <div class="mt-auto flex items-end gap-1">
       <p class="font-display text-xl lg:text-3xl font-medium text-primary">$<%= price %><%= frequency %></p>
-
-      <% if plan == "annual" %>
-        <span class="text-sm text-secondary mb-1">or <%= Money.new(price.to_f / 52).format %>/week</span>
-      <% end %>
     </div>
 
     <p class="text-sm text-secondary">
       <% if plan == "annual" %>
-        Billed annually, 2 months free
+        Charged annually
       <% else %>
-        Billed monthly
+        Charged monthly
       <% end %>
     </p>
   <% end %>