Remove use cases directory and code

[webmat]

They have not been maintained for a long time. With the recent addition
of the TLS field set (#606), the information in there was outright incorrect.

[ruflin]

I agree it needs cleanup but not sure removal is the right step here as it was a place to "share" mappings which go beyond ECS. For example the kubernetes ones. Do you have a replacement in mind?

[webmat]

Yes, there is something superior coming up soon. A description is available in the first part of this comment #601 (comment).

This will allow us and the community to share ECS mappings in a way that can also be leveraged programmatically.

[webmat]

Happy to wait until after the above project is available, if you think the use cases are still this useful.

If you think we should wait, please let me know. I'll have to fix the TLS stuff in the use cases, as it's now proposing something that's wrong.

[webmat]

• Add a changelog entry after Split changelog in two sections #633

[ruflin]

@webmat I'm ok moving forward with removing it first before we have a replacement. Sometime I pointed users to the use cases for inspiration, but having them outdated is also not good. For the replacement: Where you expect the "example csv" to end up? In this repo?

[webmat]

I'm not 100% what the end result will look like. So during the experimentation phase, I will be using a separate repo. When the POC is ready, we can look at it and decide if we should move it here or not.

[ebeahan]

We'll revisit this change when ready, but since this PR is quite out-of-date let's close.

New issue for tracking: #1391