Scala Common Enrich: add cookie extractor enrichment

[alexanderdean]

For companies using the Scala Stream Collector on a first-party domain, it would be neat to have an enrichment which could:

• Take a list of cookies you were interested in
• Generate a context for each cookie. Each cookie would have the same structure: name & value

This is neat because companies often have valuable info (e.g. about CMS sessions etc) in their first-party cookies.

This would only work currently for the Scala Stream Collector (only collector which records headers and thus cookies).

[kazjote]

I am working on it. These are my propsed json schemas:

https://github.com/snowplow/iglu-central/compare/master...RetentionGrid:cookie_extractor?expand=1

Let me know if they are ok.

[fblundun]

I think the cookie_extractor config schema looks good.

For the cookie_extractor_context - should have one context per cookie rather than all cookies in a single context? I think this would be more elegant in Redshift since we would avoid having a field containing a raw literal JSON array string.

Thoughts @yalisassoon ?

[alexanderdean]

Duplicate of #2072