This PR mainly refactors the code by extracting a "core" package which
is then used by the "backend" and "frontend" apps.
Apart from this the PR also contains several smaller changes like fixing
dependabot, upgrading dependencies, aligned "package.json" files, added
tests, ...
addresses step 1 of #32closes#136
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Co-authored-by: Marco Pasqualetti <marco.pasqualetti@live.com>
replaces
https://github.com/stats-organization/github-stats-extended/pull/96
(Thanks marcalexiei for opening that one.)
On top of rolling back the `@types/node` upgrade, this PR also upgrades
to the latest 24.x version of `@types/node` and configures dependabot to
not suggest major version upgrades for this dependency anymore.