Add Support for Specifying `VPC_ID` Per Region for EC2 Instance Creation

[dheerajoruganty]

Description:

Currently, the implementation uses the default VPC_ID for each region when launching EC2 instances. This behavior limits flexibility, as instances may need to be launched in non-default VPCs depending on the network requirements and configurations for specific regions.

The goal is to allow specifying a custom VPC_ID for each region when creating EC2 instances, overriding the default VPC configuration where needed. This will provide better control over network configurations across different AWS regions.

Requirements:

• Add support for specifying a custom VPC_ID for each region where instances are being launched.
• If no custom VPC_ID is provided for a region, continue using the default VPC for that region.
• Ensure proper validation for the VPC_ID to check whether it is valid and available in the specified region.

Possible Solutions:

• Extend the current EC2 instance creation logic to accept a VPC_ID parameter specific to each region.
• If a custom VPC_ID is specified, ensure that the instance is launched within that VPC.
• Implement validation to ensure that the VPC_ID exists and is properly configured for the region.
• If no VPC_ID is provided, use the default VPC and log that the default is being used.