Adjust instructions for K3s Storage Configuration

[Zaustie]

The K3s storage path can be adjusted easily by setting the K3S_DATA_DIR environment variable before installing K3s.

As a sidenote this should correspond to the DATADIR variable mentioned in the synapse configuration option for media_store_path and related options.

[CLAassistant]

All committers have signed the CLA.

[benbz]

Thanks for raising.

As I understand it, K3S_DATA_DIR impacts all k3s state and not just the local path provisioner storage.

I'm happy for this to change however

• It should remain in the same place in the advanced docs
• It should mention the default location of /var/lib/rancher/k3s

[Zaustie]

Oh yeah that is a good point, I'll just add it as an alternative to the original section in the advanced part of the instructions. I've also added the implementation I've actually ended up using by mounting my drive to /var during OS installation.

[benbz]

Suggested change

	If you do not mind modifying the you storage path for the entirey of K3s you can also adjust the `K3S_DATA_DIR` environment variable before installing K3s using
	If you do not mind modifying the you storage path for the entirety of K3s you can also adjust the `K3S_DATA_DIR` environment variable before installing K3s using

[benbz]

I'm happy for this to go out without a changelog entry, but if you'd like it mentioned then newsfragment/1206.doc.md needs to be added to this PR with a sentence describing the changes

[github-actions]

dyff of changes in rendered templates of CI manifests

No changes in rendered templates

[Zaustie]

I'm fine with it either way.