feat: create user scim v2 endpoint (#9132)

# Which Problems Are Solved
- Adds infrastructure code (basic implementation, error handling,
middlewares, ...) to implement the SCIM v2 interface
- Adds support for the user create SCIM v2 endpoint

# How the Problems Are Solved
- Adds support for the user create SCIM v2 endpoint under `POST
/scim/v2/{orgID}/Users`

# Additional Context

Part of #8140

internal/api/scim/serrors/errors.go

@@ -0,0 +1,140 @@
+package serrors
+
+import (
+	"context"
+	"encoding/json"
+	"errors"
+	"fmt"
+	"net/http"
+	"strconv"
+
+	"github.com/zitadel/logging"
+	"golang.org/x/text/language"
+
+	http_util "github.com/zitadel/zitadel/internal/api/http"
+	zhttp_middleware "github.com/zitadel/zitadel/internal/api/http/middleware"
+	"github.com/zitadel/zitadel/internal/api/scim/schemas"
+	"github.com/zitadel/zitadel/internal/i18n"
+	"github.com/zitadel/zitadel/internal/zerrors"
+)
+
+type scimErrorType string
+
+type wrappedScimError struct {
+	Parent   error
+	ScimType scimErrorType
+}
+
+type scimError struct {
+	Schemas       []schemas.ScimSchemaType `json:"schemas"`
+	ScimType      scimErrorType            `json:"scimType,omitempty"`
+	Detail        string                   `json:"detail,omitempty"`
+	StatusCode    int                      `json:"-"`
+	Status        string                   `json:"status"`
+	ZitadelDetail *errorDetail             `json:"urn:ietf:params:scim:api:zitadel:messages:2.0:ErrorDetail,omitempty"`
+}
+
+type errorDetail struct {
+	ID      string `json:"id"`
+	Message string `json:"message"`
+}
+
+const (
+	// ScimTypeInvalidValue A required value was missing,
+	// or the value specified was not compatible with the operation,
+	// or attribute type (see Section 2.2 of RFC7643),
+	// or resource schema (see Section 4 of RFC7643).
+	ScimTypeInvalidValue scimErrorType = "invalidValue"
+
+	// ScimTypeInvalidSyntax The request body message structure was invalid or did
+	// not conform to the request schema.
+	ScimTypeInvalidSyntax scimErrorType = "invalidSyntax"
+)
+
+var translator *i18n.Translator
+
+func ErrorHandler(next zhttp_middleware.HandlerFuncWithError) http.Handler {
+	var err error
+	translator, err = i18n.NewZitadelTranslator(language.English)
+	logging.OnError(err).Panic("unable to get translator")
+
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		if err = next(w, r); err == nil {
+			return
+		}
+
+		scimErr := mapToScimJsonError(r.Context(), err)
+		w.WriteHeader(scimErr.StatusCode)
+
+		jsonErr := json.NewEncoder(w).Encode(scimErr)
+		logging.OnError(jsonErr).Warn("Failed to marshal scim error response")
+	})
+}
+
+func ThrowInvalidValue(parent error) error {
+	return &wrappedScimError{
+		Parent:   parent,
+		ScimType: ScimTypeInvalidValue,
+	}
+}
+
+func ThrowInvalidSyntax(parent error) error {
+	return &wrappedScimError{
+		Parent:   parent,
+		ScimType: ScimTypeInvalidSyntax,
+	}
+}
+
+func (err *scimError) Error() string {
+	return fmt.Sprintf("SCIM Error: %s: %s", err.ScimType, err.Detail)
+}
+
+func (err *wrappedScimError) Error() string {
+	return fmt.Sprintf("SCIM Error: %s: %s", err.ScimType, err.Parent.Error())
+}
+
+func mapToScimJsonError(ctx context.Context, err error) *scimError {
+	scimErr := new(wrappedScimError)
+	if ok := errors.As(err, &scimErr); ok {
+		mappedErr := mapToScimJsonError(ctx, scimErr.Parent)
+		mappedErr.ScimType = scimErr.ScimType
+		return mappedErr
+	}
+
+	zitadelErr := new(zerrors.ZitadelError)
+	if ok := errors.As(err, &zitadelErr); !ok {
+		return &scimError{
+			Schemas:    []schemas.ScimSchemaType{schemas.IdError},
+			Detail:     "Unknown internal server error",
+			Status:     strconv.Itoa(http.StatusInternalServerError),
+			StatusCode: http.StatusInternalServerError,
+		}
+	}
+
+	statusCode, ok := http_util.ZitadelErrorToHTTPStatusCode(err)
+	if !ok {
+		statusCode = http.StatusInternalServerError
+	}
+
+	localizedMsg := translator.LocalizeFromCtx(ctx, zitadelErr.GetMessage(), nil)
+	return &scimError{
+		Schemas:    []schemas.ScimSchemaType{schemas.IdError, schemas.IdZitadelErrorDetail},
+		ScimType:   mapErrorToScimErrorType(err),
+		Detail:     localizedMsg,
+		StatusCode: statusCode,
+		Status:     strconv.Itoa(statusCode),
+		ZitadelDetail: &errorDetail{
+			ID:      zitadelErr.GetID(),
+			Message: zitadelErr.GetMessage(),
+		},
+	}
+}
+
+func mapErrorToScimErrorType(err error) scimErrorType {
+	switch {
+	case zerrors.IsErrorInvalidArgument(err):
+		return ScimTypeInvalidValue
+	default:
+		return ""
+	}
+}