Fix: Capture STIG Name on Upload

[vanessuniq]

• Enforced not null constraint on the name column of the stigs table.
• Updated Stig model to validate the presence of the name field.
• Updated .from_mapping method of Stig and SecurityRequirementsGuide model to capture the name when initializing the instance
• Updated Stig specs

This will ensure that every STIG has an associated name when created, and prevent display null data on the UI.