Allow options for RunAsNonRoot for poller, rrdcached and frontend

[PcInfamy]

Unlike other helm charts (including Redis and MySQL), there is no way to set runAsNonRoot to true for poller, rrdcached and frontend.

[jacobw]

I'm not sure what the impacts are of this, feel free to make a PR.

[PcInfamy]

Turns out one of the sub-dependencies requires running as root. Still investigating options here.

The main benefit would be from a security point of view - generally better to not allow root if it's not necessary, especially in a multi-tenant environment.

[jacobw]

Thanks for investigating. Which dependency?

[PcInfamy]

I think it's actually LibreNMS itself. The Docker image does a lot of chown operations on startup. I'm sure that could be restructured to allow for non-root - but that is more work than I'm willing to put in right now.

[PcInfamy]

Oh hey - looks like this might have fixed the upstream issues

librenms/docker#530