Enable Loki deployment by default in SCS observability solution

[matofeder]

As an SCS Operator, I want to use SCS observability solution as a global, horizontally scalable, highly available, multi-tenant log aggregation system. I therefore wish to enable Loki deployment by default.

Some pre-work has been already done upstream, and the Loki deployment there has been improved, see dNationCloud/kubernetes-monitoring-stack#100

Also, Loki deployment has been enabled on the SCS instance (monitoring.scs.community) of the SCS observability solution, see #50

Definition of Done:

• Enable Loki in the default HELM values file
• Test the default deployment with Loki enabled by the quickstart guide
• Test the default deployment with Loki enabled by the k3s guide
• Update docs
• Update arch diagrams