Add notifications when a badge is awarded

[harmitgoswami]

Fix #3412

This PR adds notifications to signal to a user that they received a new badge/badge level. Notifications will appear in both the "Notifications Menu" in the header (first image), and as a notification banner across the top of the page. Notification banners for new badge levels will trigger a confetti animation, imported from https://github.com/catdad/canvas-confetti.

The initial commit for this PR has a noticeable bug, in that demotions and promotions will both count towards the Community Builder Badge. This issue stems from how assign_users_to_groups will always update translators then managers, in that order. Thus, there is no way to distinguish if an action is promoting a user from Contributor -> Translator or if an action is demoting a user from Manager -> Translator, especially since multiple users can be demoted/promoted in the same action.

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 60.00000% with 24 lines in your changes missing coverage. Please review.

Project coverage is 80.36%. Comparing base (9bd457f) to head (24a3519).
Report is 5 commits behind head on main.

Additional details and impacted files

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[mathjazz]

Nice work!

As mentioned inline, I'd use a popup when the badge is awarded.

Looking into the Permission promotions bug.

[mathjazz]

Rather than "notification banners", I would use a popup similar to the new contributor popup that persists and needs to be manually hidden.

I would also show the actual badge in the popup.

[mathjazz]

The initial commit for this PR has a noticeable bug, in that demotions and promotions will both count towards the Community Builder Badge. This issue stems from how assign_users_to_groups will always update translators then managers, in that order. Thus, there is no way to distinguish if an action is promoting a user from Contributor -> Translator or if an action is demoting a user from Manager -> Translator, especially since multiple users can be demoted/promoted in the same action.

Is this not working as expected then?

pontoon/pontoon/base/forms.py

Lines 125 to 136 in 8a16a65

	# Check if user was demoted from Manager to Translator
	# In this case, it doesn't count as a promotion
	if group_name == "managers":
	removal = PermissionChangelog.objects.filter(
	performed_by=self.user,
	action_type=PermissionChangelog.ActionType.REMOVED,
	created_at__gte=now,
	)
	if removal:
	for item in removal:
	if "managers" in item.group.name:
	after_count -= 1