Add common appUtils to augment get_environment with app level data (#9236)

* Add common appUtils to augment get_environment with app level data

* Responded to code review comments

* Revert changes to dataconnect appFinder utils and manual project entry

* Use mockfs and remove available accounts line when there are no additional accounts.

* Type fix

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Co-authored-by: Joe Hanley <joehanley@google.com>

Author: schnecle