Highlight that the examples are being generated with fake / dummy data

[leonardpahlke]

Quite a few questions about the files in the examples/ folder have been if these are files generated with real data or fake data. It should get highligted that these files are based on fake data and do not leak any information.

Highlight this in the following files:

• [x] Update README.md
• [x] Add a README.md under the examples folder

cc @reylejano for suggesting this in a discussion on a related issue

ref tracking issue https://github.com/kubernetes-sigs/release-team-shadow-stats/issues/4

[leonardpahlke]

/assign