add customized login form using bootstrap (WIP)

Former-commit-id: 95debae1cd98d7441a48da8dfd2fffcd850d765b

ippisite/ippidb/templates/account/login.html

+{% extends "account/base.html" %}
+
+{% load i18n %}
+{% load account socialaccount %}
+
+{% block head_title %}{% trans "Sign In" %}{% endblock %}
+
+{% block content %}
+
+<div class="d-flex justify-content-center">
+
+    <div class="card" style="width: 18rem;">
+        <div class="card-header">
+            <h1>{% trans "Sign In" %}</h1>
+        </div>
+        <div class="card-body">
+            {% get_providers as socialaccount_providers %}
+
+            {% if socialaccount_providers %}
+                <p>{% blocktrans with site.name as site_name %}Please sign in with one
+        of your existing third party accounts. Or, <a href="{{ signup_url }}">sign up</a>
+        for a {{ site_name }} account and sign in below:{% endblocktrans %}</p>
+
+            <div class="socialaccount_ballot">
+
+              <ul class="socialaccount_providers">
+                {% include "socialaccount/snippets/provider_list.html" with process="login" %}
+              </ul>
+
+              <div class="login-or">{% trans 'or' %}</div>
+
+            </div>
+
+            {% include "socialaccount/snippets/login_extra.html" %}
+
+            {% else %}
+            <p>{% blocktrans %}If you have not created an account yet, then please
+            <a href="{{ signup_url }}">sign up</a> first.{% endblocktrans %}</p>
+            {% endif %}
+
+            <form class="login" method="POST" action="{% url 'account_login' %}">
+              {% csrf_token %}
+              {{ form.as_p }}
+              {% if redirect_field_value %}
+              <input type="hidden" name="{{ redirect_field_name }}" value="{{ redirect_field_value }}" />
+              {% endif %}
+              <a class="btn btn-secondary" href="{% url 'account_reset_password' %}">{% trans "Forgot Password?" %}</a>
+              <button class="btn btn-primary" type="submit">{% trans "Sign In" %}</button>
+            </form>
+        </div>
+    </div>
+
+
+</div>
+{% endblock %}