Periodically clean continous sync db

[LesnyRumcajs]

Issue summary

A workaround for https://github.com/ChainSafe/forest/issues/1708

On the test machine, we need a mechanism (e.g. daily cronjob) that would check whether we're good in terms of memory and if not, prune the sync volume. Then we would need to download a new snapshot (at least for mainnet for the time being) and import it to bootstrap everything again.

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