Allow headers to be ignored from interaction matching

[aoberoi]

Description

This feature request is from #64.

Headers often contain data that is meant to change from one replay to another. That means when the headers are recorded into the interaction, they can sometimes undesirably affect interaction matching. Here are a few ideas on how we might solve this:

• As suggested in the ticket above, create a blacklist of headers to ignore.
• Provide a way to turn off recording of anything but the required headers (such as Content-Type).
• Provide a whitelist of headers to include.

We should also create a config setting for whichever solution we use so that users don't have to repeat this over and over. (#4)

Requirements (place an x in each of the [ ])

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• I've searched for any related issues and avoided creating a duplicate issue.