Update project's Maintenance and Troubleshooting guide
Created by: matofeder
This PR updates the Maintenance and Troubleshooting Guide for SCS k8s-cluster-api-provider from v0.2 to v0.3. Update prettifies guide formatting, and adds some useful links and commands for maintenance and troubleshooting.
@garloff @chess-knight @jschoone if you have in mind some specific Maintenance and Troubleshooting scenarios that should be added prior to R4, please let me know, glad to add them.
Closes #377 (closed)