Add validation to ensure workflow spec is within file size limits

[fernandol-nvidia]

What new feature or improvement would you like to see?

1. Determine a reasonable spec limit we allow
2. Enforce spec limit during workflow submission
3. Make the spec limit configurable by admins

Why is this needed?

Prevent DOS from very large workflows

Code of Conduct

• I agree to follow NVIDIA OSMO's Code of Conduct
• I have searched the open feature requests and have found no duplicates for this feature request