feat: implement AddZitadelProvider in ManagementService (#12056)

# Which Problems Are Solved

This PR adds implementation to add a Zitadel IdP at the
organization-level.

# How the Problems Are Solved
- Added handling/converters for the `AddZitadelProvider` endpoint in
`ManagementService` in the server layer
- Registered a new `org.idp.zitadel.added` event for org-level Zitadel
providers
- Added `AddOrgZitadelProvider` command to validate the request and push
`org.idp.zitadel.added` event to the eventstore
- Added the `org.idp.zitadel.added` event to the projection reducer
- Added unit and integration tests

# Additional Changes
added more tests for the ZitadelProvider in AdminService

# Additional Context
- Closes https://github.com/zitadel/zitadel/issues/11823
- Follow-up for PRs https://github.com/zitadel/zitadel/pull/12018,
https://github.com/zitadel/zitadel/pull/12020,
https://github.com/zitadel/zitadel/pull/12055

internal/command/instance_idp_test.go

@@ -6094,6 +6094,46 @@ func TestCommandSide_AddInstanceZitadelIDP(t *testing.T) {
 				},
 			},
 		},
+		{
+			name: "ok, without instance roles info",
+			fields: fields{
+				eventstore: expectEventstore(
+					expectFilter(),
+					expectPush(
+						instance.NewZitadelIDPAddedEvent(context.Background(), &instance.NewAggregate("instance1").Aggregate,
+							"id1",
+							"name",
+							"issuer",
+							"clientID",
+							&crypto.CryptoValue{
+								CryptoType: crypto.TypeEncryption,
+								Algorithm:  "enc",
+								KeyID:      "id",
+								Crypted:    []byte("clientSecret"),
+							},
+							nil,
+							idp.Options{},
+							nil,
+						),
+					),
+				),
+				idGenerator:  id_mock.NewIDGeneratorExpectIDs(t, "id1"),
+				secretCrypto: crypto.CreateMockEncryptionAlg(gomock.NewController(t)),
+			},
+			args: args{
+				ctx: authz.WithInstanceID(context.Background(), "instance1"),
+				provider: ZitadelProvider{
+					Name:         "name",
+					Issuer:       "issuer",
+					ClientID:     "clientID",
+					ClientSecret: "clientSecret",
+				},
+			},
+			res: res{
+				id:   "id1",
+				want: &domain.ObjectDetails{ResourceOwner: "instance1"},
+			},
+		},
 		{
 			name: "ok",
 			fields: fields{