Birth dates, birthday reminders API, allow instance admins to require minimum age

Signed-off-by: marcin mikołajczak <git@mkljczk.pl>

priv/repo/migrations/29220116183110_add_birth_date_to_users.exs

@@ -0,0 +1,10 @@
+defmodule Pleroma.Repo.Migrations.AddBirthDateToUsers do
+  use Ecto.Migration
+
+  def change do
+    alter table(:users) do
+      add_if_not_exists(:birth_date, :date)
+      add_if_not_exists(:hide_birth_date, :boolean, default: false, null: false)
+    end
+  end
+end

priv/static/schemas/litepub-0.1.jsonld

@@ -35,7 +35,8 @@
             "alsoKnownAs": {
                 "@id": "as:alsoKnownAs",
                 "@type": "@id"
-            }
+            },
+            "vcard": "http://www.w3.org/2006/vcard/ns#"
         }
     ]
 }