Store translation activity data in a separate table

[mathjazz]

We'd like to move some of the Translation metadata related to user activity to a separate table:

pontoon/pontoon/base/models/translation.py

Lines 113 to 157 in 44ab754

	# Active translations are displayed in the string list and as the first
	# entry in the History tab. There can only be one active translation for
	# each (entity, locale, plural_form) combination. See bug 1481175.
	active = models.BooleanField(default=False)
	pretranslated = models.BooleanField(default=False)
	fuzzy = models.BooleanField(default=False)
	approved = models.BooleanField(default=False)
	approved_user = models.ForeignKey(
	User,
	models.SET_NULL,
	related_name="approved_translations",
	null=True,
	blank=True,
	)
	approved_date = models.DateTimeField(null=True, blank=True)
	unapproved_user = models.ForeignKey(
	User,
	models.SET_NULL,
	related_name="unapproved_translations",
	null=True,
	blank=True,
	)
	unapproved_date = models.DateTimeField(null=True, blank=True)
	rejected = models.BooleanField(default=False)
	rejected_user = models.ForeignKey(
	User,
	models.SET_NULL,
	related_name="rejected_translations",
	null=True,
	blank=True,
	)
	rejected_date = models.DateTimeField(null=True, blank=True)
	unrejected_user = models.ForeignKey(
	User,
	models.SET_NULL,
	related_name="unrejected_translations",
	null=True,
	blank=True,
	)
	unrejected_date = models.DateTimeField(null=True, blank=True)

See also #3443.

[eemeli]

The idea here would be to add a new table, something like TranslationActions, which would provide a per-entity-locale timestamped stream of approve/reject/add-fuzzy/pretranslate actions that would provide the information currently retained in the corresponding Translation status fields. The current status of an entity in a given locale would be determined by looking at the most recent action.

This could also replace a large part of ActionLog as well as ChangedEntityLocale.