Lower the concurrency settings in the default project template. (#6918)

* Lower the concurrency settings in the default project template.

* Simplify the concurrency settings template.

Author: wRAR

scrapy/templates/project/module/settings.py.tmpl

@@ -21,16 +21,10 @@ ADDONS = {}
 # Obey robots.txt rules
 ROBOTSTXT_OBEY = True
 
-# Configure maximum concurrent requests performed by Scrapy (default: 16)
-#CONCURRENT_REQUESTS = 32
-
-# Configure a delay for requests for the same website (default: 0)
-# See https://docs.scrapy.org/en/latest/topics/settings.html#download-delay
-# See also autothrottle settings and docs
-#DOWNLOAD_DELAY = 3
-# The download delay setting will honor only one of:
-#CONCURRENT_REQUESTS_PER_DOMAIN = 16
-#CONCURRENT_REQUESTS_PER_IP = 16
+# Concurrency and throttling settings
+#CONCURRENT_REQUESTS = 16
+CONCURRENT_REQUESTS_PER_DOMAIN = 1
+DOWNLOAD_DELAY = 1
 
 # Disable cookies (enabled by default)
 #COOKIES_ENABLED = False