Add network egress resource (#357)

This change adds a new import resource which enables exposing Netbird
resources as Kubernetes services. This remove the need to add sidecars
to every pod.

<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->
## Summary by CodeRabbit

* **New Features**
* Added a new `NetworkEgress` custom resource (`netbird.io/v1alpha1`)
with CRD, schema validation, and status/conditions.
* Extended controller functionality to create egress services and
translate egress rules into import `EndpointSlice` resources; egress
pods now include a kube-egress-forwarder sidecar.
* **Bug Fixes**
* Added missing deep-copy and declarative apply support for the new
`NetworkEgress` API types.
* **Documentation**
* Updated README/API reference and added example manifests for
`NetworkEgress` (including IP/FQDN target usage).
<!-- end of auto-generated comment: release notes by coderabbit.ai -->

Signed-off-by: Philip Laine <philip.laine@gmail.com>

pkg/applyconfigurations/api/v1alpha1/networkegressstatus.go

@@ -0,0 +1,47 @@
+// SPDX-License-Identifier: BSD-3-Clause
+
+// Code generated by controller-gen. DO NOT EDIT.
+
+package v1alpha1
+
+import (
+	v1 "k8s.io/client-go/applyconfigurations/meta/v1"
+)
+
+// NetworkEgressStatusApplyConfiguration represents a declarative configuration of the NetworkEgressStatus type for use
+// with apply.
+//
+// NetworkEgressStatus defines the observed state of NetworkEgress.
+type NetworkEgressStatusApplyConfiguration struct {
+	// ObservedGeneration is the last reconciled generation.
+	ObservedGeneration *int64 `json:"observedGeneration,omitempty"`
+	// Conditions holds the conditions for the NetworkEgress.
+	Conditions []v1.ConditionApplyConfiguration `json:"conditions,omitempty"`
+}
+
+// NetworkEgressStatusApplyConfiguration constructs a declarative configuration of the NetworkEgressStatus type for use with
+// apply.
+func NetworkEgressStatus() *NetworkEgressStatusApplyConfiguration {
+	return &NetworkEgressStatusApplyConfiguration{}
+}
+
+// WithObservedGeneration sets the ObservedGeneration field in the declarative configuration to the given value
+// and returns the receiver, so that objects can be built by chaining "With" function invocations.
+// If called multiple times, the ObservedGeneration field is set to the value of the last call.
+func (b *NetworkEgressStatusApplyConfiguration) WithObservedGeneration(value int64) *NetworkEgressStatusApplyConfiguration {
+	b.ObservedGeneration = &value
+	return b
+}
+
+// WithConditions adds the given value to the Conditions field in the declarative configuration
+// and returns the receiver, so that objects can be build by chaining "With" function invocations.
+// If called multiple times, values provided by each call will be appended to the Conditions field.
+func (b *NetworkEgressStatusApplyConfiguration) WithConditions(values ...*v1.ConditionApplyConfiguration) *NetworkEgressStatusApplyConfiguration {
+	for i := range values {
+		if values[i] == nil {
+			panic("nil value passed to WithConditions")
+		}
+		b.Conditions = append(b.Conditions, *values[i])
+	}
+	return b
+}