WIP: Add AWS EBS disk evidence type and processor

[aarontp]

WIP

Description of the change

Adds a new AwsEbsVolume evidence type for AWS EBS disks and the related pre/post-processors so we can attach and mount these disks.

Other notes:

• Moves IsBlockDevice() to util module
• Requires CLOUD_PROVIDER in config to be set to AWS
• Adds a new AWS_ZONE config parameter for the default zone.

Applicable issues

Fixes #1318

Additional information

Only certain disk types are compatible with multi-attach so this first iteration will only support those types, and for other disk types we'll only be able to support a single worker for now. In future PRs we'll try to come up with a method to process these disks, possibly by making a copy of the disk with a disk type that supports multi-attach.

Checklist

• All tests were successful.
• Unit tests added.
• Documentation updated.

[jleaniz]

@aarontp is this PR still in progress?

[aarontp]

@jleaniz Yes, I just need to find the time to test it end-to-end and make sure everything works in AWS. I've tested the code by writing a wrapper around the evidence class and running pre-processors, but not when running as part of an actual processing run. I'll see if I can get to this this week.