feat(awslambda): add new check `awslambda_function_vpc_is_in_multiple_az`

[puchy22]

Context

New check that ensures AWS Lambda functions connected to a Virtual Private Cloud (VPC) are distributed across multiple Availability Zones (AZs). This is crucial for maintaining high availability and resilience, as deploying Lambda functions in a single AZ can lead to a single point of failure, potentially disrupting operations if that AZ becomes unavailable.

Description

• [x] Modify service to add Subnets to AWS Lambda Functions
• [x] Test service changes
• [x] Add configurable parameter for the check
• [x] Add check logic
• [x] Add unit testing for the check

Checklist

• Are there new checks included in this PR? Yes
  • If so, do we need to update permissions for the provider? No.
• [x] Review if the code is being covered by tests.
• [x] Review if code is being documented following this specification https://github.com/google/styleguide/blob/gh-pages/pyguide.md#38-comments-and-docstrings

License

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.