Show sats instead of BTC on donation page, refactor CSS

* Show sats instead of BTC on donation page
* Use number delimiters on both donation page and wallet page
* Refactor donation page CSS into Tailwind directives

app/views/donations/index.html.erb

@@ -8,19 +8,22 @@
 
 <section>
   <% if @donations.any? %>
-    <ul class="donations">
+    <ul class="donations list-none">
       <% @donations.each do |donation| %>
-        <li>
-          <h3>
+        <li class="mb-8 grid gap-y-2 gap-x-8 grid-cols-2 items-center">
+          <h3 class="mb-0">
             <%= donation.paid_at.strftime("%B %d, %Y") %>
           </h3>
-          <p class="amount-btc">
-            <%= sats_to_btc donation.amount_sats %> BTC
+          <p class="row-span-2 font-mono text-right mb-0">
+            <span class="text-xl">
+              <%= number_with_delimiter donation.amount_sats %> sats
+            </span>
+            <br>
+            <span class="text-sm text-gray-500">
+              (~ <%= number_to_currency donation.amount_eur / 100, unit: "" %> EUR)
+            </span>
           </p>
-          <p class="amounts-fiat">
-            (~ <%= number_to_currency donation.amount_eur / 100, unit: "" %> EUR)
-          </p>
-          <p class="public-name">
+          <p class="mb-0">
             <% if donation.public_name.present? %>
               Public name: <%= donation.public_name %>
             <% else %>