Is your feature request related to a problem? Please describe.

As observed during #261, users can accidentally set timeouts inconsistently. A concrete example is that one can set a User facing timeout lower than any backend timeout, such that requests may fail early.

Describe the solution you'd like

We should provide some sanity checking to prevent unintended timeout behavior.

Currently, the "future-proofing" unit testing strategy is buried in a GitHub PR comment, which amounts to "tribal knowledge." salesforce/policy_sentry#254 (comment)

To avoid the negative effects of tribal knowledge on OSS governance, we should move this to the documentation under the contribution section.

Gotta make sure this tool works across multiple operating systems and Python versions. The biggest concern is the graph file-storage, since that's OS-specific code and I could only test against Ubuntu 16.

Principal Mapper needs to be tested on the following operating systems and Python versions (but not all combinations of which):

Python

• Python 3.6
• Python 3.7

Operati

#22 introduced a feature to guess actions that are similar to an existing policy. It currently doesn't support all actions.

Here's things I currently know are missing (comment if you find more):

• KMS: Encrypt, Decrypt, GenerateDataKey, ...
• ECR: BatchDeleteImage, BatchGetImage, ...
• *Deregister*
• *Modify*
• *Remove*
• API Gateway: (DELETE,