web: progressively backfill all bulk collections

[l5yth]

Fix #832

[codecov]

Codecov Report

❌ Patch coverage is 99.02320% with 8 lines in your changes missing coverage. Please review.
✅ All tests successful. No failed tests found.

Files with missing lines	Patch %	Lines
...assets/js/app/main/__tests__/data-fetchers.test.js	96.20%	6 Missing ⚠️
.../js/app/__tests__/main-collection-backfill.test.js	99.29%	2 Missing ⚠️

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