Move scrapy to its own module and add patch to fix broken permission code.

Scrapy is usually installed via pip where copying all permissions
makes sense. In Nix the files copied are owned by root and
readonly. As a consequence scrapy can't edit the project templates so

  scrapy startproject

fails.

pkgs/development/python-modules/scrapy/permissions-fix.patch

@@ -0,0 +1,28 @@
+diff --git a/scrapy/commands/startproject.py b/scrapy/commands/startproject.py
+index 5941066..89f8edb 100644
+--- a/scrapy/commands/startproject.py
++++ b/scrapy/commands/startproject.py
+@@ -4,7 +4,7 @@ import os
+ import string
+ from importlib import import_module
+ from os.path import join, exists, abspath
+-from shutil import ignore_patterns, move, copy2, copystat
++from shutil import ignore_patterns, move, copyfile, copystat
+ 
+ import scrapy
+ from scrapy.commands import ScrapyCommand
+@@ -76,8 +76,7 @@ class Command(ScrapyCommand):
+             if os.path.isdir(srcname):
+                 self._copytree(srcname, dstname)
+             else:
+-                copy2(srcname, dstname)
+-        copystat(src, dst)
++                copyfile(srcname, dstname)
+ 
+     def run(self, args, opts):
+         if len(args) not in (1, 2):
+@@ -118,4 +117,3 @@ class Command(ScrapyCommand):
+         _templates_base_dir = self.settings['TEMPLATES_DIR'] or \
+             join(scrapy.__path__[0], 'templates')
+         return join(_templates_base_dir, 'project')
+-