Rework examples, migrate to new GAM instance & rethink JSFiddle

[muuki88]

The examples have helped a lot of people to understand prebid, but they have not aged too good. We should take our chance and rework the examples from the ground up

• Gather and categorize examples. What works, what is relevant, what is out-dated
• Evaluate putting the example code directly in the prebid docs repo and remove JS Fiddle as a dependency. The main reason for JS Fiddle was that the code was readable and executed on the page
• Add step by step what happens in the ad server ( GAM ) - what line items are targeted and why
• Move away from the Xandr GAM instance to @patmmccann test instance

Related

• Should create an example page for Native ads #5047
• Broken floors example #4933
• Should create an example page for Prebid & Safeframes #5067
• Deletion of deal rendering module, replacing with example #4535
• Prebid Video Samples Are Not Playing Ads #2182
• All Instream prebid-server examples are broken #4311
• Update video examples to not rely on a bidder being available and willing to bid #5248