Expose the worker join timer values added in cozystack/cozystack#3898 #33

Upstream cozystack/cozystack#3898 added three optional values to the kubernetes and kubernetes-nodes charts: maxNodeProvisionTime, nodeHealthCheck.readyUnknownTimeout, and nodeHealthCheck.readyFalseTimeout. The provider cannot set any of them today: the kubernetes resource models a node_health_check block in internal/provider/kubernetes_schema.go but carries neither timeout, the kubernetes_nodes resource has no node_health_check block at all, and maxNodeProvisionTime appears in neither schema.

All three are Go duration strings validated at chart render time. Zero and negative values are rejected, and the canonical serialized form a Go duration prints ("20m0s", "1h0m0s") is accepted, per cozystack/cozystack#3901.

The fields are optional with chart-side defaults (30m, 5m, 10m), so omitting them stays backward compatible; the provider only needs to pass them through when set.