feat: add --initialPermissions flag to reduce execution time

[maniSbindra]

Summary

This PR implements the --initialPermissions flag (closes #91) which allows users to specify permissions upfront to reduce MPF execution time. This also provides a workaround for the Terraform remote backend issue (#172).

Changes

New Feature: --initialPermissions flag

• Added as a global flag available to all commands (arm, bicep, terraform)
• Supports two formats:
  • Comma-separated list: --initialPermissions "perm1,perm2,perm3"
  • JSON file reference: --initialPermissions @path/to/file.json

Implementation

• parseInitialPermissions() - Parses comma-separated or @file.json format
• appendUserInitialPermissions() - Helper to reduce code duplication across commands
• IterationCount field added to MPFResult to track discovery iterations

Testing

• Added TestParseInitialPermissions unit tests for parsing logic
• Added TestTerraformACIWithInitialPermissions e2e test that verifies 0 iterations when all permissions are provided upfront

Documentation

• Updated commandline-flags-and-env-variables.md with usage examples
• Added "Remote Backend Access Denied" section to known-issues-and-workarounds.MD

Use Cases

1. Reduce execution time - Seed known permissions to skip discovery iterations
2. Terraform remote backend - Provide storage account permissions before MPF runs
3. CI/CD pipelines - Use cached permission files from previous runs

Example Usage

# Comma-separated
azmpf terraform --initialPermissions "Microsoft.Storage/storageAccounts/read,Microsoft.Storage/storageAccounts/listKeys/action" ...

# From file
azmpf terraform --initialPermissions @backend-permissions.json ...

Related Issues

• Closes Provide option/flag to specify initial minimum permissions that the mpf utility should initialize with #91
• Provides workaround for [Bug]: terraform with remote backend; ampf removes the permission it needs to interact with the backend state store #172