Rewrite socialaccount login template

Mitigates #438

aleksis/core/templates/socialaccount/login.html

+{% extends "core/base.html" %}
+
+{% load i18n material_form account %}
+
+{% block browser_title %}{% trans "Authorize" %}{% endblock %}
+{% block page_title %}{% trans "Authorize" %}{% endblock %}
+
+{% block content %}
+{% if process == "connect" %}
+    <p class="flow-text">
+       <i class="material-icons left">info</i>
+       {% blocktrans with provider.name as provider %}You are about to connect a new third party account from {{ provider }}.{% endblocktrans %}
+    </p>
+    <form method="post">
+      {% csrf_token %}
+      {% form form=form %}{% endform %}
+      {% trans "Confirm" as caption %}
+      {% include "core/partials/save_button.html" with caption=caption icon="how_to_reg" %}
+    </form>
+{% else %}
+    <p class="flow-text">
+       <i class="material-icons left small">info</i>
+       {% blocktrans with provider.name as provider %}You are about to sign in using a third party account from {{ provider }}.{% endblocktrans %}
+    </p>
+    <form method="post">
+      {% csrf_token %}
+      {% form form=form %}{% endform %}
+      {% trans "Continue" as caption %}
+      {% include "core/partials/save_button.html" with caption=caption icon="how_to_reg" %}
+    </form>
+
+{% endif %}
+{% endblock %}