[WIP] Proposal add initial bdd testing

[RyanJarv]

I was thinking since one of the stated goals of this project is to document IAM quirks, BDD testing may make sense as a way to easily understand what what is and isn't expected in various cases.

This is just a minimal work in progress currently, and will likely need more thought, but put together this PR to get an idea of what this might look like and hopefully get some feedback in case this might be something you all would be interested in merging once it's further along.

[Skybound1]

Hey Ryan, I'll be honest, I had never heard of BDD testing before this 😂 I did some Googling, and it looks decent for what you are proposing, so I'd be up for using it to document the fun bits of AWS IAM 😁

🤔 My current thinking is that we use this in parallel with the current integration testing we have... moreso that this can be used to document those quirks with base examples and make sure we don't regress on them. That way we don't pollute those feature files with too much of the same overarching thing (ie 5 different tests for the same feature in IAM). Does that kinda align with what you were thinking?