Blue: Add bidFloor and currency param. Change current values configuration.

[samuelfabel]

This pull request refers to:

1. Adding two new parameters, bidFloor and currency, to the bidder-params of the Blue bidder.
2. Updating the placementId parameter to make it required.

🏷 Type of documentation

• new bid adapter
• update bid adapter
• new feature
• text edit only (wording, typos)
• bugfix (code examples)
• new examples

📋 Checklist

• Related pull requests in prebid.js or server are linked Blue: Add bidFloor and currency param. Change current values configuration. prebid.github.io#5784
• For new adapters check submitting your adapter docs

[github-actions]

Code coverage summary

Note:

• Prebid team doesn't anticipate tests covering code paths that might result in marshal and unmarshal errors
• Coverage summary encompasses all commits leading up to the latest one, bec988b

blue

Refer here for heat map coverage report

github.com/prebid/prebid-server/v3/adapters/blue/blue.go:20:	Builder		100.0%
github.com/prebid/prebid-server/v3/adapters/blue/blue.go:28:	MakeRequests	85.7%
github.com/prebid/prebid-server/v3/adapters/blue/blue.go:49:	MakeBids	100.0%
total:								(statements)	95.8%

[samuelfabel]

We decided that we will do another implementation.