Merge pull request #5244 from Azure/FromPublicRepo

From public repo
Merge pull request #5245 from Azure/master

master
Merge pull request #5246 from Azure/DailyPub

Daily pub
Add prerequisites section
Merge pull request #5247 from Azure/AUX4112

Aux4112
Fix download links
hdinsight-hadoop-storm-scpdotnet-csharp-develop-streaming-data-processing-application.md added per tfs 15692
Merge branch 'master' of https://github.com/Azure/azure-content into ptvs21
Merge pull request #5249 from Azure/AUX4113

Aux4113
Updated TOC and anchors
placeholder tutorials for mobile dev centers
Updating authors & metadata for iOS topics
placeholder tutorials for mobile dev centers
Updating authors & metadata for iOS topics
Updating authors & metadata for iOS topics
placeholder tutorials for mobile dev centers
Add images alt text and made the links to images inline
ML additional articles + edit to old articles
ML Retail demand doc update
Merge pull request #5255 from jaymathe/dp-jm

ML additional articles + edit to old articles