Add badge to nav for number of waiting invoices

Might slightly help us stop leaving them waiting for far too long...

templates/base.html

@@ -31,12 +31,12 @@
 <a class="skip-link" href='#main'>Skip to content</a>
 {% include "analytics.html" %}
 {% block navbar %}
-<nav class="navbar navbar-expand-lg navbar-dark bg-dark flex-nowrap" role="navigation">
+<nav class="navbar navbar-expand-lg navbar-dark bg-dark flex-nowrap text-nowrap" role="navigation">
   <a class="navbar-brand" href="{% if request.user.is_authenticated %}https://members.nottinghamtec.co.uk{%else%}https://nottinghamtec.co.uk{%endif%}">
     <img src="{% static 'imgs/logo.webp' %}" width="40" height="40" alt="TEC's Logo: Serif 'TEC' vertically next to a blue box with the words 'PA and Lighting', surrounded by graduated rings" id="logo">
   </a>
   <div class="container" style="padding-left: 0; padding-right: 0;">
-    <div class="row w-100">
+    <div class="row">
       {% block titleheader %}
       {% endblock %}
       <button class="navbar-toggler ml-auto" type="button" data-toggle="collapse" data-target="#navbarSupportedContent" aria-controls="navbarSupportedContent" aria-expanded="false" aria-label="Toggle navigation" onclick="document.getElementById('logo').classList.toggle('d-none');">