main: silence all logrus logging for now

[mvo5]

This commit silences logrus logging for now by just dicarding everything from it. The rational is that the underlying libraries produce a lot of output, e.g. every build currently results in

$ image-builder build qcow2
WARN[0000] Failed to load consumer certs: no consumer key found
...

which is confusing to our users. What is worse is that containers also uses logrus so we can get random warnings without context from there too. Until we have a way to filter log messages this seems to be the most practical way.

We can add --verbose or --debug later to enable these kinds of messages.

[supakeen]

Agreed; I'll open a ticket to track a --verbose (or multiple -v's).

[lzap]

This is fine, I plan to refactor composer/images to make use of the stdlib log/slog but that is the same story and a similar solution.

Alternatively you can grab my ring buffer writer implementation from a different project and use it here storing last N lines, when error occurs you can pickup the data from the ring buffer and display it.

tw := NewTailWriter(2<<10)
logrus.SetOutput(tw)

// ... when error occurs

println(tw.LastLines(20))