Compute default value of calico autodetection in s-c-c rather than sylva-core

Close: #1477 (closed)

In the case of rke2, the solution is to calculate the default value for canReach in the s-c-c chart (this is already the case here https://gitlab.com/sylva-projects/sylva-elements/helm-charts/sylva-capi-cluster/-/blob/main/templates/_machine-files.tpl?ref_type=heads#L404). Since s-c-c knows the value of the IP allocated by the heatOperator, the value of canReach will be correct as soon as s-c-c is instantiated.

The other solution would be to reintroduce sylva-unit reconciliation at bootstrap level (removed via !809 (merged)). This introduces more complexity, but if other fields/values are affected by this behaviour, then this will be the right solution.