Update MRF docs, make sample code actually compile

See merge request pleroma/pleroma!2210

# Conflicts:
#   docs/configuration/mrf.md

Fix MRF documentation

See merge request pleroma/pleroma!2187

Additional config description improvements

See merge request pleroma/pleroma!2207

Fix `status.expires_at` type

Closes #1573

See merge request pleroma/pleroma!2222

# Conflicts:
#	test/web/admin_api/admin_api_controller_test.exs

Standardize @behaviour usage in MRFs

See merge request pleroma/pleroma!2212

need_reboot flag for adminFE

See merge request pleroma/pleroma!2188

Update floki to 0.25

See merge request pleroma/pleroma!2217

Update adminFE build

See merge request pleroma/pleroma!2221

Update plug_crypto

See merge request pleroma/pleroma!2219

.gitattributes: use native support for elixir definitions

See merge request pleroma/pleroma!2218

see https://github.com/elixir-lang/elixir/pull/9823

MastodonAPI.StatusView: Do not use site_name

See merge request pleroma/pleroma!2216

site_name allow to spoof the origin of the domain and so hacks like:

<!-- served on https://hacktivis.me/tmp/joinmastodon.org.html -->
<meta property="og:image" content="https://hacktivis.me/datalove/img/meme/pleroma/mastodon%2C%20forbidden%20amuse%20yourself.jpeg" />
<meta property="og:title" content="Mastodon: Forbidden Amuse Yourself" />
<meta property="og:site_name" content="joinmastodon.org" />
<meta http-equiv="refresh" content="0; url=http://joinmastodon.org/">

Move ex_syslogger & recon to hexpm, update dependencies

See merge request pleroma/pleroma!2213

Upgraded:
  db_connection 2.2.0 => 2.2.1
  earmark 1.4.2 => 1.4.3
  ecto 3.3.1 => 3.3.3
  ecto_sql 3.3.2 => 3.3.4
  esshd 0.1.0 => 0.1.1
  ex_doc 0.21.2 => 0.21.3
  excoveralls 0.12.1 => 0.12.2
  gettext 0.17.1 => 0.17.4
  html_entities 0.5.0 => 0.5.1
  httpoison 1.6.1 => 1.6.2
  joken 2.1.0 => 2.2.0
  jose 1.9.0 => 1.10.1
  nimble_parsec 0.5.1 => 0.5.3
  phoenix 1.4.10 => 1.4.13
  phoenix_ecto 4.0.0 => 4.1.0
  phoenix_html 2.13.3 => 2.14.0
  plug_cowboy 2.1.0 => 2.1.2
  plug_crypto 1.1.0 => 1.1.1
  prometheus 4.4.1 => 4.5.0
  tesla 1.3.0 => 1.3.2

Update ferd/recon

See merge request pleroma/pleroma!2211

integrating with an MRF.

Upstream changelog:

2.5.0
- Optional formatting of records in traces (thanks to @bartekgorny)
- Basic support for OTP-22 in recon_alloc (base handling of foreign_blocks type)

NodeInfo: Fix federating status not being reported when MRF transparency is disabled

Closes #1568

See merge request pleroma/pleroma!2206

Fix the confusingly named and inverted logic of "no_attachment_links"

See merge request pleroma/pleroma!2202

deps: update back fast sanitize

See merge request pleroma/pleroma!2205