Normalize existing data to NFC

[aurimasv]

Follow-up from #542

All inputs and outputs from DB are currently being normalized, but existing data in the DB is still npt guaranteed to be normalized (it does get normalized during sync though, I believe).

Helpful info from the other issue that should help optimize this process:

A quote from the Unicode standard annex 15:

Text exclusively containing ASCII characters (U+0000..U+007F) is left unaffected by all of the Normalization Forms. ... Text exclusively containing Latin-1 characters (U+0000..U+00FF) is left unaffected by NFC. This is effectively the same as saying that all Latin-1 text is already normalized to NFC.