create project and backer scope to get backers and projects that have confirmed backer on current day
change the project owner new backer confirmed notification to send one time per day when have a new confirmed backer [Fix #60979604]
use notify_once with date filter
use projects created_at to avoid ambigous created_at from backers
Merge pull request #460 from devton/confirmed_backers_info

Change project owner confirmed backer notification to send one time per day with confirmed backers resume ;)