improvements and fixes for http requests

- fix for gun worker termination in some circumstances
- pool for http clients (ex_aws, tzdata)
- default pool timeouts for gun
- gun retries on gun_down messages
- s3 upload timeout if streaming enabled

lib/pleroma/http/ex_aws.ex

@@ -11,6 +11,8 @@ defmodule Pleroma.HTTP.ExAws do
 
   @impl true
   def request(method, url, body \\ "", headers \\ [], http_opts \\ []) do
+    http_opts = Keyword.put(http_opts, :adapter, pool: :upload)
+
     case HTTP.request(method, url, body, headers, http_opts) do
       {:ok, env} ->
         {:ok, %{status_code: env.status, headers: env.headers, body: env.body}}