fix: Validation for Resource Limits

[Hacks4Snacks]

Description

Intermittently we are observing unexpected and invalid memory resource limits being set for the ScanJob pods.

Example:
trivy-system scan-vulnerabilityreport-5594588b7b-w9m7l 500m (3%) 750m (4%) 512Mi (1%) 1288490188800m (3%) 7s

Operator Log:
{"level":"info","ts":"2024-07-26T07:42:18Z","logger":"KubeAPIWarningLogger","msg":"spec.template.spec.containers[6].resources.limits[memory]: fractional byte value \"1288490188800m\" is invalid, must be an integer"}

As such, this PR introduces validations in config.go for ResourceMemory, ResourceEphemeralStorage, and ResourceCPU to ensure the values passed from the configuration (or default) are valid as well as validating the parsed values match the expected values to prevent unexpected resource allocations.

Additionally, this PR updates the documentation to use the Mi unit for memory allocation as it is more commonly used in Kubernetes configurations

Related issues

• No existing bug

Checklist

• I've read the guidelines for contributing to this repository.
• I've added tests that prove my fix is effective or that my feature works.
• I've updated the documentation with the relevant information (if needed).
• I've added usage information (if the PR introduces new options)
• I've included a "before" and "after" example to the description (if the PR is a user interface change).

[github-actions]

This PR is stale because it has been labeled with inactivity.