Add requirements.txt to scripts
Add requirements.txt to scripts

The Python scripts depend on several packages. Specify dependencies in
requirements.txt as is expected.

Change-Id: I564718a8fd2a3e3728293d1947829b1164b69306

Duct-and-rice/KrswtkhrWiki4Android,wikimedia/apps-android-wikipedia,carloshwa/apps-android-wikipedia,wikimedia/apps-android-wikipedia,SAGROUP2/apps-android-wikipedia,SAGROUP2/apps-android-wikipedia,carloshwa/apps-android-wikipedia,Duct-and-rice/KrswtkhrWiki4Android,SAGROUP2/apps-android-wikipedia,Duct-and-rice/KrswtkhrWiki4Android,Duct-and-rice/KrswtkhrWiki4Android,anirudh24seven/apps-android-wikipedia,anirudh24seven/apps-android-wikipedia,carloshwa/apps-android-wikipedia,dbrant/apps-android-wikipedia,SAGROUP2/apps-android-wikipedia,carloshwa/apps-android-wikipedia,dbrant/apps-android-wikipedia,anirudh24seven/apps-android-wikipedia,Duct-and-rice/KrswtkhrWiki4Android,anirudh24seven/apps-android-wikipedia,dbrant/apps-android-wikipedia,carloshwa/apps-android-wikipedia,wikimedia/apps-android-wikipedia,dbrant/apps-android-wikipedia,dbrant/apps-android-wikipedia,wikimedia/apps-android-wikipedia,SAGROUP2/apps-android-wikipedia,anirudh24seven/apps-android-wikipedia