Media.net Analytics and Bid Adapter: import common functions

[patmmccann]

  _getAttributeFromSelector and other adjacent functions should be imported by both adapters. 

• modules/medianetAnalyticsAdapter.js has 11 duplicated lines with modules/medianetBidAdapter.js

Reducing code duplication by importing common functions from a library not only makes our code cleaner but also easier to maintain. Please move the common code from both files into a library and import it in each. Keep up the great work! 🚀

Originally posted by @github-actions[bot] in #11924 (comment)

[patmmccann]

cc @adish1997 @adish-r