Add custom themes, THEME setting, basic "yolocolo" theme (#7)

Specify `THEME=yourtheme`, add some HTML files in `capsulflask/theme/yourtheme` 👌

We probably want to reduce copypasta in the current `yolocolo` theme by using template inheritance, at some point.

Reviewed-on: #7
Co-authored-by: 3wordchant <3wordchant@noreply.git.autonomic.zone>
Co-committed-by: 3wordchant <3wordchant@noreply.git.autonomic.zone>

capsulflask/theme/yolocolo/account-balance.html

@@ -0,0 +1,94 @@
+{% extends 'base.html' %}
+
+{% block title %}Account Balance{% endblock %}
+
+{% block content %}
+<div class="row third-margin">
+  <h1>Account Balance: ${{ account_balance }}</h1>
+</div>
+<div class="half-margin">
+ 
+  {% if has_vms and has_payments and warning_text != "" %}
+  <div class="row">
+    <pre class="wrap">{{ warning_text }}</pre>
+  </div>
+  {% endif %}
+  <div class="row">
+    {% if has_payments %}
+    <div>
+      <div class="row third-margin">
+        <h1>Payments</h1>
+      </div>
+    
+      <table>
+        <thead>
+          <tr>
+            <th>amount</th>
+            <th>date</th>
+          </tr>
+        </thead>
+        <tbody>
+          {% for payment in payments %}
+            <tr>
+              <td class="{{ payment['class_name'] }}">${{ payment["dollars"] }}</td>
+              <td class="{{ payment['class_name'] }}">{{ payment["created"] }}</td>
+            </tr>
+          {% endfor %}
+        </tbody>
+      </table>
+    </div>
+    {% endif %}
+    <ul>
+      <li>
+        <h1>PAYMENT OPTIONS</h1>
+        <ul>
+          <li>
+            <a href="/payment/stripe">Add funds with Credit/Debit (stripe)</a>
+            <ul><li>notice: stripe will load nonfree javascript </li></ul>
+          </li>
+          {% if btcpay_enabled %}
+          <li><a href="/payment/btcpay">Add funds with Bitcoin/Litecoin/Monero (btcpay)</a></li>
+          {% endif %}
+        </ul>
+      </li>
+    </ul>
+
+  </div>
+
+
+  {% if has_vms %}
+  <div class="row third-margin">
+    <h1>Capsuls Billed</h1>
+  </div>
+  <div class="row">
+    <table class="small">
+      <thead>
+        <tr>
+          <th>id</th>
+          <th>created</th>
+          <th>deleted</th>
+          <th>$/month</th>
+          <th>months</th>
+          <th>$ billed</th>
+        </tr>
+      </thead>
+      <tbody>
+        {% for vm in vms_billed %}
+          <tr>
+            <td>{{ vm["id"] }}</td>
+            <td>{{ vm["created"] }}</td>
+            <td>{{ vm["deleted"] }}</td>
+            <td>${{ vm["dollars_per_month"] }}</td>
+            <td>{{ vm["months"] }}</td>
+            <td>${{ vm["dollars"] }}</td>
+          </tr>
+        {% endfor %}
+      </tbody>
+    </table>
+  </div>
+  
+  {% endif %}
+</div>
+{% endblock %}
+
+{% block pagesource %}/templates/create-capsul.html{% endblock %}