Allow custom links to other systems (monitoring tools etc)

[hjacobs]

There should be a simple way to add custom links for resources (clusters, applications, teams) to link to external systems, e.g. monitoring dashboards or similar.

Each link definition should have:

• href/URL with templating (using Python string formatting), e.g. https://mon.example.org/clusters/{id} would generate a link to https://mon.example.org/clusters/123 for the cluster with ID 123
• title (tooltip)
• icon (Fontawesome icon name)

[hjacobs]

This was implemented and documented on https://github.com/hjacobs/kube-resource-report#custom-links

TODO: also allow linking nodes (e.g. to a monitoring dashboard), ingress and other entities