fix: use fs stores by default in Dockerfile

[achingbrain]

This is to better align with Kubo's behaviour and also stops the containers running out of memory really quickly since in-memory stores aren't really meant for production use.

Also turns on metrics by default and explicitly enables sub domains.

Change checklist

• I have performed a self-review of my own code
• I have made corresponding changes to the documentation if necessary (this includes comments as well)
• I have added tests that prove my fix is effective or that my feature works