feat: genTsigKey and refresh tsig key

chore: update mod name and dependencies

chore: implement changes from linters, update copyright years

feat: manual updating of A records

feat: apikey refreshing and eye toggle

fix: a possible flaw to delete domains owned by others

fix: check A record in update api, move check to func

feat: some logging improvements

feat: check that domains are only ascii letters and numbers

feat: don't allow full stops in domains

fix: typo in error

refactor: move more to handlers

refactor: directory layout

feat: adding and deleting of domains