new NO_BID event and "no bids" available from auction

[snapwich]

Type of change

• Bugfix
• Feature

Description of change

Added the a new event NO_BID which is fired for analytics and anything else interested in bidders not bidding. Since no bid is created when not bidding, the NO_BID event sends the bid request that the bidder was notified of but decided not to respond to. The auction also keeps track of these bid requests that resulted in no bid and makes them available through a new API call pbjs.getNoBids(), this is primarily for the updated debug snippet in prebid/prebid.github.io#1030

Also added a fix for a potential bug with the new done callback refactoring (in #3024). The updated logic was relying on counting which can be problematic (for instance, if one bidder calls done more than once that could potentially end the auction early). New logic only ends auction if done has been heard from each bidder with a bidderRequest.

Other information

fixes #2640 and is a replacement solution for #3022

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.

[jaiminpanchal27]

LGTM.

[idettman]

LGTM

[mkendall07]

sorry for the delay. Will get to this PR this week.

[mkendall07]

LGTM. I think we just need a docs PR for the new method?

[GLStephen]

@mkendall07 @snapwich hey we're waiting on this for an update to our analytics adapter, can I contribute to the docs and help with getting this moved along or is it in progress?

[mkendall07]

@GLStephen nothing on my end in progress - feel free to work on it. Thanks!

[snapwich]

Sorry, thought I had already documented everything. The snippet has been updated but I guess we should add documentation for the new API method; just created a new pull-request for that feature.

[GLStephen]

@snapwich @mkendall07 looks like docs are done, do you think this can make it into the next release?