fix: remove authentication requirement from diagnostics endpoint

Merge remote-tracking branch 'origin/master'

refactor: replace most custom date util functions by lancet ones

refactor: add precision mode to missing intervals function

chore: metrics performance improvements

feat: ability to clear all user data (resolve muety#339)

fix: hotfix for muety#337 (resolve muety#33)

chore: remove entity index again

chore: add migration note

chore: bump version

chore: easier setup instructions (resolve muety#325)

fix: branches chart (resolve muety#322)