Show conference CFP deadlines

Closes: #105

agenda/conference.py

@@ -33,6 +33,8 @@ class Conference:
     currency: str | None = None
     latitude: float | None = None
     longitude: float | None = None
+    cfp_end: date | None = None
+    cfp_url: str | None = None
 
     @property
     def display_name(self) -> str:

templates/conference_list.html

@@ -3,7 +3,7 @@
 {% from "macros.html" import trip_link, conference_row with context %}
 
 {% block style %}
-{% set column_count = 7 %}
+{% set column_count = 8 %}
 <style>
 .grid-container {
   display: grid;

templates/macros.html

@@ -31,6 +31,7 @@
   </div>
   <div class="grid-item">{{ item.topic }}</div>
   <div class="grid-item">{{ item.location }}</div>
+  <div class="grid-item text-end">{{ display_date(item.cfp_end) if item.cfp_end else "" }}</div>
   <div class="grid-item">
     {% if country %}
       {{ country.flag }} {{ country.name }}