feat(kubernetes/shell): kubectl web shell and kubeconfig functionality EE-448 (#5229)

* feat(kubernetes/shell): backport kubectl shell backend functionality EE-849 (#5168)

* backported core backend kubectl shell functionality

* - backported kubectl shell unit tests
- backported k8s cli interface update
- backported k8s client library fake patch

* refactored backend to match EE

* fixed test error typo

* GetServiceAccountName -> GetServiceAccount - making the function reusable in multiple contexts

* feat(kubernetes/shell): backport kubeconfig generation backend functionality EE-1004 (#5213)

* backported core backend kubectl shell functionality

* refactored backend to match EE

* - backported kubernetes backend handler implementation
- backported kubernetes config endpoint
- backported kubeconfig file generation
- backported kubeconfig and yaml unit tests
- backported updates to kubeclient interfaces

* feat(app): kubectl shell ui backport EE-927 (#5221)

* Kubectl UI backport to CE

* fix authentication redirect issue

* comment out redirect function

* fix shell full width & change name of shell

* disable button when terminal connected

* fixed whitespace changes for css

* fixed whitespace changes for html

* linting fixes

Co-authored-by: zees-dev <dev.786zshan@gmail.com>

* feat(kubernetes/shell): backport of kubeconfig export functionality EE-926 (#5228)

* EE backport of kubeconfig UI functionality

* using angularjs constant instead of hardcoded URL

* updated portainer kubectl shell image

* fix kubectl button position issue in ce

* fix pod keep running when switching page

* feat(app): Kubectl shell ui EE-833 EE-1099 (#5271)

* fix kubectl shell css

* fix mini css issue

* fix tech issue for ui changes from review

* delete unuse file

* - refactored variable names
- restored content-wrapper scroll
- created object to store wrapper css

Co-authored-by: zees-dev <dev.786zshan@gmail.com>

* addressing PR issues

* fix required changes from tech reviews (#5319)

* fix required changes from tech reviews

* remove unuse css variable

* component refactor accoridng to PR and style guidelines

Co-authored-by: zees-dev <dev.786zshan@gmail.com>

* removed redundant dockerhub api endpoint variable

* - autoHeight -> terminal-window
- removed redundant try-catch
- saving config.yaml file as config

* fix(kube/shell): show error on failure

* fixed default https bug

* resolved merge conflicts

Co-authored-by: Richard Wei <54336863+WaysonWei@users.noreply.github.com>
Co-authored-by: richard <richard@richards-iMac-Pro.local>
Co-authored-by: Chaim Lev-Ari <chiptus@gmail.com>

api/http/handler/handler.go

@@ -16,6 +16,7 @@ import (
 	"github.com/portainer/portainer/api/http/handler/endpointproxy"
 	"github.com/portainer/portainer/api/http/handler/endpoints"
 	"github.com/portainer/portainer/api/http/handler/file"
+	"github.com/portainer/portainer/api/http/handler/kubernetes"
 	"github.com/portainer/portainer/api/http/handler/motd"
 	"github.com/portainer/portainer/api/http/handler/registries"
 	"github.com/portainer/portainer/api/http/handler/resourcecontrols"
@@ -47,6 +48,7 @@ type Handler struct {
 	EndpointHandler        *endpoints.Handler
 	EndpointProxyHandler   *endpointproxy.Handler
 	FileHandler            *file.Handler
+	KubernetesHandler      *kubernetes.Handler
 	MOTDHandler            *motd.Handler
 	RegistryHandler        *registries.Handler
 	ResourceControlHandler *resourcecontrols.Handler
@@ -100,6 +102,8 @@ type Handler struct {
 // @tag.description Manage Docker environments
 // @tag.name endpoint_groups
 // @tag.description Manage endpoint groups
+// @tag.name kubernetes
+// @tag.description Manage Kubernetes cluster
 // @tag.name motd
 // @tag.description Fetch the message of the day
 // @tag.name registries
@@ -156,6 +160,8 @@ func (h *Handler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 		http.StripPrefix("/api", h.EdgeTemplatesHandler).ServeHTTP(w, r)
 	case strings.HasPrefix(r.URL.Path, "/api/endpoint_groups"):
 		http.StripPrefix("/api", h.EndpointGroupHandler).ServeHTTP(w, r)
+	case strings.HasPrefix(r.URL.Path, "/api/kubernetes"):
+		http.StripPrefix("/api", h.KubernetesHandler).ServeHTTP(w, r)
 	case strings.HasPrefix(r.URL.Path, "/api/endpoints"):
 		switch {
 		case strings.Contains(r.URL.Path, "/docker/"):