wurfl-devicedetection module enhancements

[andreacastello]

🔧 Type of changes

• module update

✨ What's the context?

What's the context for the changes?

• WURFL Module device enrichment improvements

🧠 Rationale behind the change

Why did you choose to make these changes? Were there any trade-offs you had to consider?

• Improving deviceType classification during device enrichment phase
• Skipping enrichment if device has been already enriched (ie: via a javascript module from prebid.js)

🧪 Test plan

How do you know the changes are safe to ship to production?

• New unit tests added

🏎 Quality check

• Are your changes following our code style guidelines?
• Are there any breaking changes in your code?
• Does your test coverage exceed 90%?
• Are there any erroneous console logs, debuggers or leftover code in your changes?