1763: Index tests r=MarinPostma a=MarinPostma
This pr aims to test more thorougly the usage on index in the meilisearch database, by writing unit tests.
work included:
- [x] Create index mock and stub methods
- [x] Test snapshot creation
- [x] Test Dumps
- [x] Test search
Co-authored-by: mpostma <postma.marin@protonmail.com>