feat: remember the value of import overwrite

fix: show address in backup results tree (closes #35)

feat: add v2 backup import

fix: disallow closing import backup modal

fix: split import errors and warnings

refactor: rename 'friend' to 'contact'

fix: remove more debug info (closes #32)

fix: correct backup export version

feat: export wallets

fix: remove some debugging lines (closes #25)

i18n: add empty count keys

refactor: remove react import (react v17)

feat: more utils for translators

feat: near completion with v1 backup importing

refactor: split up Wallet.ts

feat: backup results tree

fix: re-add onCancel to ImportBackupModal

feat: more backup import progress

fix: replace ant-design Upload with bare html ...

The Upload component added 24 kB to the bundle, which was pretty
ridiculous considering we were only using 1% of its features.

feat: more progress on backup import

refactor: import aliases

feat: begin work on backup importing