Doc imp (#13148)

* added intro, item and prices video, fixed image links in item and prices

* update 2: first 5 videos added

* added all videos to the user manual

* updated .gitignore
diff --git a/.gitignore b/.gitignore
index d641ced..68272c7 100644
--- a/.gitignore
+++ b/.gitignore
@@ -10,4 +10,5 @@
 erpnext/docs/current
 *.swp
 *.swo
+__pycache__
 *~