fix resources parameter to accept just cpu and/or memory

[nickdallavalentina]

Issue #, if available:

There is no validation on the parameter that are passed to -resources then you can pass whatever parameter,
example how to replicate:

eks-node-viewer -resources memories

Description of changes:

This change adds validation for the -resources flag to ensure that only the values "cpu" and/or "memory" are accepted. If any invalid resource is provided (e.g., "memoryss"), the application will return an error. The update includes a helper function to validate the comma-separated list of resources

[tzneal]

There are other resource types (e.g. pods, ephemeral-storage or GPU resources) that might be useful to display. I don't think we should limit it to just cpu and memory.