Refactor Core things, including Ecto handling, ActivityPub & Transmogrifier modules

* Data doesn't need anymore to be converted to ActivityStream format to
be saved (this was taken from Pleroma and not at all a good idea here)
* Everything saved when creating an event is inserted into PostgreSQL in
a single transaction

lib/service/activity_pub/utils.ex

@@ -238,8 +238,8 @@ defmodule Mobilizon.Service.ActivityPub.Utils do
   @doc """
   Save picture data from %Plug.Upload{} and return AS Link data.
   """
-  def make_picture_data(%Plug.Upload{} = picture) do
-    case MobilizonWeb.Upload.store(picture) do
+  def make_picture_data(%Plug.Upload{} = picture, opts) do
+    case MobilizonWeb.Upload.store(picture, opts) do
       {:ok, picture} ->
         picture
 
@@ -636,18 +636,39 @@ defmodule Mobilizon.Service.ActivityPub.Utils do
   Make create activity data
   """
   @spec make_create_data(map(), map()) :: map()
-  def make_create_data(params, additional \\ %{}) do
+  def make_create_data(object, additional \\ %{}) do
     Logger.debug("Making create data")
-    Logger.debug(inspect(params))
-    published = params.published || make_date()
+    Logger.debug(inspect(object))
+    Logger.debug(inspect(additional))
 
     %{
       "type" => "Create",
-      "to" => params.to |> Enum.uniq(),
-      "actor" => params.actor.url,
-      "object" => params.object,
-      "published" => published,
-      "id" => params.object["id"] <> "/activity"
+      "to" => object["to"],
+      "cc" => object["cc"],
+      "actor" => object["actor"],
+      "object" => object,
+      "published" => make_date(),
+      "id" => object["id"] <> "/activity"
+    }
+    |> Map.merge(additional)
+  end
+
+  @doc """
+  Make update activity data
+  """
+  @spec make_update_data(map(), map()) :: map()
+  def make_update_data(object, additional \\ %{}) do
+    Logger.debug("Making update data")
+    Logger.debug(inspect(object))
+    Logger.debug(inspect(additional))
+
+    %{
+      "type" => "Update",
+      "to" => object["to"],
+      "cc" => object["cc"],
+      "actor" => object["actor"],
+      "object" => object,
+      "id" => object["id"] <> "/activity"
     }
     |> Map.merge(additional)
   end
@@ -688,6 +709,22 @@ defmodule Mobilizon.Service.ActivityPub.Utils do
     }
   end
 
+  @doc """
+  Make accept join activity data
+  """
+  @spec make_accept_join_data(map(), map()) :: map()
+  def make_accept_join_data(object, additional \\ %{}) do
+    %{
+      "type" => "Accept",
+      "to" => object["to"],
+      "cc" => object["cc"],
+      "actor" => object["actor"],
+      "object" => object,
+      "id" => object["id"] <> "/activity"
+    }
+    |> Map.merge(additional)
+  end
+
   @doc """
   Converts PEM encoded keys to a public key representation
   """