Remove old tables from PROD database

[grst]

in nf_core_stats_bot.github.pipelines the watchers_count column is identical to the stargazers_count column

[grst]

ok, I've seen there's also a nfcore_pipelines table where this seems fixed.

So is one of them outdated? Can unused tables be deleted?

[grst]

So which tables are not used anymore besides pipelines. Would be great to cleanup the motherduck instance.