Disable attachment links by default

Closes #1394

CHANGELOG.md

@@ -10,6 +10,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 
 ### Changed
 - **Breaking:** Elixir >=1.8 is now required (was >= 1.7)
+- **Breaking:** attachment links (`config :pleroma, :instance, no_attachment_links` and `config :pleroma, Pleroma.Upload, link_name`) disabled by default
 - Replaced [pleroma_job_queue](https://git.pleroma.social/pleroma/pleroma_job_queue) and `Pleroma.Web.Federator.RetryQueue` with [Oban](https://github.com/sorentwo/oban) (see [`docs/config.md`](docs/config.md) on migrating customized worker / retry settings)
 - Introduced [quantum](https://github.com/quantum-elixir/quantum-core) job scheduler
 - Enabled `:instance, extended_nickname_format` in the default config

config/config.exs

@@ -90,7 +90,7 @@ config :pleroma, Pleroma.Captcha.Kocaptcha, endpoint: "https://captcha.kotobank.
 config :pleroma, Pleroma.Upload,
   uploader: Pleroma.Uploaders.Local,
   filters: [Pleroma.Upload.Filter.Dedupe],
-  link_name: true,
+  link_name: false,
   proxy_remote: false,
   proxy_opts: [
     redirect_on_failure: false,
@@ -257,7 +257,7 @@ config :pleroma, :instance,
   mrf_transparency_exclusions: [],
   autofollowed_nicknames: [],
   max_pinned_statuses: 1,
-  no_attachment_links: false,
+  no_attachment_links: true,
   welcome_user_nickname: nil,
   welcome_message: nil,
   max_report_comment_size: 1000,