Adds the content for lesson 13, fixes some code inconsistencies for the services code in the examples, and adds this lesson to the navigation.
PR Close#49980
Each individual lesson should have the images available in the download since a learner can start from any lesson. So, we're adding images here. Also, sync'ing styles for consistency across the lessons. This is fixing some previous commits that didn't include these changes. The goal is that for future commits we can have less changes and focused solely on that lesson
PR Close#49980
