Remove release_env

While taking a final look at instance.gen before releasing I noticed
that the release_env task outputs messages in broken english. Upon
further inspection it seems to have even more severe issues which, in
my opinion, warrant it's at least temporary removal:
- We do not explain what it actually does, anywhere. Neither the task
 docs nor instance.gen, nor installation instructions.
- It does not respect FHS on OTP releases (uses /opt/pleroma/config even
 though we store the config in /etc/pleroma/config.exs).
- It doesn't work on OTP releases, which is the main reason it exists.
Neither systemd nor openrc service files for OTP include it.
- It is not mentioned in install guides other than the ones for Debian
and OTP releases.

lib/mix/tasks/pleroma/instance.ex

@@ -36,9 +36,7 @@ defmodule Mix.Tasks.Pleroma.Instance do
           listen_port: :string,
           strip_uploads: :string,
           anonymize_uploads: :string,
-          dedupe_uploads: :string,
-          skip_release_env: :boolean,
-          release_env_file: :string
+          dedupe_uploads: :string
         ],
         aliases: [
           o: :output,
@@ -243,24 +241,6 @@ defmodule Mix.Tasks.Pleroma.Instance do
 
       write_robots_txt(static_dir, indexable, template_dir)
 
-      if Keyword.get(options, :skip_release_env, false) do
-        shell_info("""
-        Release environment file is skip. Please generate the release env file before start.
-        `MIX_ENV=#{Mix.env()} mix pleroma.release_env gen`
-        """)
-      else
-        shell_info("Generation the environment file:")
-
-        release_env_args =
-          with path when not is_nil(path) <- Keyword.get(options, :release_env_file) do
-            ["gen", "--path", path]
-          else
-            _ -> ["gen"]
-          end
-
-        Mix.Tasks.Pleroma.ReleaseEnv.run(release_env_args)
-      end
-
       shell_info(
         "\n All files successfully written! Refer to the installation instructions for your platform for next steps."
       )

lib/mix/tasks/pleroma/release_env.ex

@@ -1,76 +0,0 @@
-# Pleroma: A lightweight social networking server
-# Copyright © 2017-2020 Pleroma Authors <https://pleroma.social/>
-# SPDX-License-Identifier: AGPL-3.0-only
-
-defmodule Mix.Tasks.Pleroma.ReleaseEnv do
-  use Mix.Task
-  import Mix.Pleroma
-
-  @shortdoc "Generate Pleroma environment file."
-  @moduledoc File.read!("docs/administration/CLI_tasks/release_environments.md")
-
-  def run(["gen" | rest]) do
-    {options, [], []} =
-      OptionParser.parse(
-        rest,
-        strict: [
-          force: :boolean,
-          path: :string
-        ],
-        aliases: [
-          p: :path,
-          f: :force
-        ]
-      )
-
-    file_path =
-      get_option(
-        options,
-        :path,
-        "Environment file path",
-        "./config/pleroma.env"
-      )
-
-    env_path = Path.expand(file_path)
-
-    proceed? =
-      if File.exists?(env_path) do
-        get_option(
-          options,
-          :force,
-          "Environment file already exists. Do you want to overwrite the #{env_path} file? (y/n)",
-          "n"
-        ) === "y"
-      else
-        true
-      end
-
-    if proceed? do
-      case do_generate(env_path) do
-        {:error, reason} ->
-          shell_error(
-            File.Error.message(%{action: "write to file", reason: reason, path: env_path})
-          )
-
-        _ ->
-          shell_info("\nThe file generated: #{env_path}.\n")
-
-          shell_info("""
-          WARNING: before start pleroma app please make sure to make the file read-only and non-modifiable.
-            Example:
-              chmod 0444 #{file_path}
-              chattr +i #{file_path}
-          """)
-      end
-    else
-      shell_info("\nThe file is exist. #{env_path}.\n")
-    end
-  end
-
-  def do_generate(path) do
-    content = "RELEASE_COOKIE=#{Base.encode32(:crypto.strong_rand_bytes(32))}"
-
-    File.mkdir_p!(Path.dirname(path))
-    File.write(path, content)
-  end
-end