[FEATURE] Add support for more instance types

[dbwiddis]

Is your feature request related to a problem?

Selection of instance types is limited by the cpuArch context to a specific size of Compute-Optimized instance.

opensearch-cluster-cdk/lib/infra/infra-stack.ts

Lines 86 to 87 in d3b12a8

	const ec2InstanceType = (props.cpuType === AmazonLinuxCpuType.X86_64)
	? InstanceType.of(InstanceClass.C5, InstanceSize.XLARGE) : InstanceType.of(InstanceClass.C6G, InstanceSize.XLARGE);

Some plugins or extensions require other instance types, such as memory optimized for Anomaly Detection HCAD (See opensearch-project/opensearch-sdk-java#652 and https://aws.amazon.com/blogs/big-data/detect-anomalies-on-one-million-unique-entities-with-amazon-opensearch-service/)

What solution would you like?

Allow a user to specify the instance type for each node type.

What alternatives have you considered?

Manually changing the instance types in the infra-stack.ts code.

Do you have any additional context?

Using T instance for development work costs less money while figuring things out!

See also #6

[jordarlu]

Thank you, @dbwiddis ..
@rishabh6788 will comment , and in the mean time, it will be great if you can also contribue on the changes in PR ..

[rishabh6788]

#30 PR to add more choices for data and ml nodes. @dbwiddis