feat(nodeinfo): extract and save NodeInfo information from instances to display it on instances list

We also try to detect the application actor if it's not given by NodeInfo metadata (FEP-2677)
(guessing for Mobilizon, PeerTube & Mastodon).

Closes #1392

Signed-off-by: Thomas Citharel <tcit@tcit.fr>

lib/mobilizon/instances/instance_actor.ex

@@ -0,0 +1,39 @@
+defmodule Mobilizon.Instances.InstanceActor do
+  @moduledoc """
+  An instance actor
+  """
+  use Ecto.Schema
+  import Ecto.Changeset
+  alias Mobilizon.Actors.Actor
+
+  @type t :: %__MODULE__{
+          domain: String.t(),
+          actor: Actor.t(),
+          instance_name: String.t(),
+          instance_description: String.t(),
+          software: String.t(),
+          software_version: String.t()
+        }
+
+  schema "instance_actors" do
+    field(:domain, :string)
+    field(:instance_name, :string)
+    field(:instance_description, :string)
+    field(:software, :string)
+    field(:software_version, :string)
+    belongs_to(:actor, Actor)
+
+    timestamps()
+  end
+
+  @required_attrs [:domain]
+  @optional_attrs [:actor_id, :instance_name, :instance_description, :software, :software_version]
+  @attrs @required_attrs ++ @optional_attrs
+
+  def changeset(%__MODULE__{} = instance_actor, attrs) do
+    instance_actor
+    |> cast(attrs, @attrs)
+    |> validate_required(@required_attrs)
+    |> unique_constraint(:domain)
+  end
+end