add isPublic to dashboard (#48012)

adds toggle to make a dashboard public

* config struct for public dashboard config
* api endpoints for public dashboard configuration
* ui for toggling public dashboard on and off
* load public dashboard config on share modal

Co-authored-by: Owen Smallwood <owen.smallwood@grafana.com>
Co-authored-by: Torkel Ödegaard <torkel@grafana.com>

pkg/services/dashboards/dashboard_provisioning_mock.go

@@ -1,4 +1,4 @@
-// Code generated by mockery v2.10.0. DO NOT EDIT.
+// Code generated by mockery v2.12.1. DO NOT EDIT.
 
 package dashboards
 
@@ -7,6 +7,8 @@ import (
 
 	models "github.com/grafana/grafana/pkg/models"
 	mock "github.com/stretchr/testify/mock"
+
+	testing "testing"
 )
 
 // FakeDashboardProvisioning is an autogenerated mock type for the DashboardProvisioningService type
@@ -170,3 +172,13 @@ func (_m *FakeDashboardProvisioning) UnprovisionDashboard(ctx context.Context, d
 
 	return r0
 }
+
+// NewFakeDashboardProvisioning creates a new instance of FakeDashboardProvisioning. It also registers the testing.TB interface on the mock and a cleanup function to assert the mocks expectations.
+func NewFakeDashboardProvisioning(t testing.TB) *FakeDashboardProvisioning {
+	mock := &FakeDashboardProvisioning{}
+	mock.Mock.Test(t)
+
+	t.Cleanup(func() { mock.AssertExpectations(t) })
+
+	return mock
+}