Add Support for Loops and Conditional Operations in Workflow

[jorgeMFS]

We need to implement control flow operations (loops and conditionals) in the workflow builder to enable more complex genomic data processing scenarios.
Features needed:

1. For/while Loop Implementation:

• Allow iteration over multiple files
• Support running operations X number of times
• Visual representation of loop blocks in the workflow
• Loop parameter configuration (iteration count, file selection)

2. Conditional (If) Implementation:

• Add conditions based on file properties or operation results
• Support basic comparison operators (equals, greater than, less than, etc.)
• Allow nested conditions within loops

Technical Considerations:

• Modify the workflow state structure in App.js to support nested operations
• Update the RecipePanel component to handle and display nested operations
• Extend the exportRecipe utility to generate appropriate shell script loops and conditions

Acceptance Criteria:

• Users can add loops and conditions through the UI
• Nested operations are visually distinct in the workflow
• Generated shell scripts correctly implement the control flow
• Control flow operations can be saved and loaded with recipes