Remove dangling server file (#1206)

That was moved to hanami/cli [1]

[1] - https://github.com/hanami/cli/blob/main/lib/hanami/cli/server.rb

lib/hanami/server.rb

@@ -1,29 +0,0 @@
-# frozen_string_literal: true
-
-require "hanami"
-require "rack"
-
-module Hanami
-  # Rack compatible server.
-  #
-  # It is run with:
-  #
-  #   `bundle exec hanami server`
-  #
-  # It runs the app, by using the server specified in your `Gemfile`
-  # (eg. Puma or Unicorn).
-  #
-  # @since 0.8.0
-  # @api private
-  class Server < ::Rack::Server
-    # Primarily this removes the ::Rack::Chunked middleware
-    # which is the cause of Safari content-length bugs.
-    #
-    # @since 0.8.0
-    def middleware
-      mw = ::Hash.new { |e, m| e[m] = [] }
-      mw["development"].concat([::Rack::ShowExceptions, ::Rack::Lint])
-      mw
-    end
-  end
-end