Allow fetching EBS volumes

[bombergio]

With this PR adding new config argument ec2.ebs_volumes to fetch EC2 EBS volumes.

[James-Quigley]

A few comments:

• I think types that are int64 should correspond to BigInt?
• I think this is the right schema from the SDK right? https://pkg.go.dev/github.com/aws/aws-sdk-go-v2@v0.24.0/service/ec2#Volume If so, I don't see throughput in the schema, and it seems like Attachments were omitted
• Need to run the generator for the mocks to update the ec2 service mock, and then need to implement the mock test for ec2 Volumes. Follow the instructions in https://github.com/cloudquery/cq-provider-aws/blob/main/adding_a_new_resource.md

[bombergio]

You are referencing outdated EC2 SDK - v 0.24.0, while I was using v 1.2.0 (and the same version is used in the module )
As you can see in the EC2 v1.2.0, all integer fields are of type int32 and there is a field name throughput.
Thanks for pointing to missing Attachments and mocks, I'll add them in the next commit.

[yevgenypats]

@bombergio Thanks! Merging.