Add examples to user_data Object with the raw, normalized & sha256 values

[ericduran]

I initially tried to add the examples to the original table as another column but because the SHA256 hashes are rather long it shrinks the description column and prioritized the example column which wasn't the goal.

So I ended up adding the examples below the user data table, I went with an impression example so I left out certain fields like click_id, or landing page out.

I sourced examples from known reference so the GPP example is from the GPP repo, and also added a normalization table for the examples to highlight the raw value being normalized before being SHA256.

I place the example right below the user_data table but happy to move it down to a reference section if we think that makes more sense.