docs: add section about Node.js log levels (#462)
docs: add section about Node.js log levels (#462)

* docs: add section about Node.js log levels

Signed-off-by: Lance Ball <637094cbcafd6c4c397ebad24eca1a25fa2cf312@redhat.com>

* squash: updated to also support logLevel in func.yaml

Signed-off-by: Lance Ball <637094cbcafd6c4c397ebad24eca1a25fa2cf312@redhat.com>
knative/func,knative/func,knative/func,knative/func,knative/func,knative/func,knative/func