Migrate `diff-list`, `diff-accounts` and `diff-transactions` to typescript

Putting to WIP waiting for !1146 (merged) to be merged.

This MR fixes the following error :

server/lib/diff-list.js:6:13 - error TS2322: Type 'any' is not assignable to type 'never'.

6             scoreMatrix[i][j] = computePairScore(knowns[i], provideds[j]);