Add the GUI set-of-mark object detector data collection script

mm_agents/gui_som/data_preparation/README.md

@@ -0,0 +1,8 @@
+1. Get the URLs from majestic_million and save them to `majestic_million.csv`
+```bash
+python3 majestic_million.py
+```
+2. Run scrapy spider to get the data from the URLs
+```bash
+python scrapy_crawler.py
+```