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/mobilizon/actors/actor.ex

@@ -13,6 +13,7 @@ defmodule Mobilizon.Actors.Actor do
   alias Mobilizon.Media.File
   alias Mobilizon.Reports.{Note, Report}
   alias Mobilizon.Users.User
+  alias Mobilizon.Mention
 
   alias MobilizonWeb.Endpoint
   alias MobilizonWeb.Router.Helpers, as: Routes
@@ -46,6 +47,7 @@ defmodule Mobilizon.Actors.Actor do
           created_reports: [Report.t()],
           subject_reports: [Report.t()],
           report_notes: [Note.t()],
+          mentions: [Mention.t()],
           memberships: [t]
         }
 
@@ -139,6 +141,7 @@ defmodule Mobilizon.Actors.Actor do
     has_many(:created_reports, Report, foreign_key: :reporter_id)
     has_many(:subject_reports, Report, foreign_key: :reported_id)
     has_many(:report_notes, Note, foreign_key: :moderator_id)
+    has_many(:mentions, Mention)
     many_to_many(:memberships, __MODULE__, join_through: Member)
 
     timestamps()

lib/mobilizon/actors/actors.ex

@@ -88,7 +88,10 @@ defmodule Mobilizon.Actors do
   """
   @spec get_actor_by_url(String.t(), boolean) ::
           {:ok, Actor.t()} | {:error, :actor_not_found}
-  def get_actor_by_url(url, preload \\ false) do
+  def get_actor_by_url(url, preload \\ false)
+  def get_actor_by_url(nil, _preload), do: {:error, :actor_not_found}
+
+  def get_actor_by_url(url, preload) do
     case Repo.get_by(Actor, url: url) do
       nil ->
         {:error, :actor_not_found}