New Adapter: Seedtag

[sangarbe]

🔧 Type of changes

• [x] new bid adapter
• [ ] bid adapter update
• [ ] new feature
• [ ] new analytics adapter
• [ ] new module
• [ ] module update
• [ ] bugfix
• [ ] documentation
• [ ] configuration
• [ ] dependency update
• [ ] tech debt (test coverage, refactorings, etc.)

✨ What's the context?

What's the context for the changes? https://github.com/prebid/prebid-server-java/issues/3787

🧠 Rationale behind the change

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

🔎 New Bid Adapter Checklist

• [x] verify email contact works
• [x] NO fully dynamic hostnames
• [x] geographic host parameters are NOT required
• [ ] direct use of HTTP is prohibited - implement an existing Bidder interface that will do all the job
• [ ] if the ORTB is just forwarded to the endpoint, use the generic adapter - define the new adapter as the alias of the generic adapter
• [x] cover an adapter configuration with an integration test

🧪 Test plan

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

🏎 Quality check

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