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/resources/user_metadata.go

@@ -0,0 +1,150 @@
+package resources
+
+import (
+	"context"
+	"encoding/json"
+	"time"
+
+	"github.com/zitadel/logging"
+	"golang.org/x/text/language"
+
+	"github.com/zitadel/zitadel/internal/api/scim/metadata"
+	"github.com/zitadel/zitadel/internal/api/scim/schemas"
+	"github.com/zitadel/zitadel/internal/api/scim/serrors"
+	"github.com/zitadel/zitadel/internal/command"
+	"github.com/zitadel/zitadel/internal/zerrors"
+)
+
+func (h *UsersHandler) mapMetadataToCommands(ctx context.Context, user *ScimUser) ([]*command.AddMetadataEntry, error) {
+	md := make([]*command.AddMetadataEntry, 0, len(metadata.ScimUserRelevantMetadataKeys))
+	for _, key := range metadata.ScimUserRelevantMetadataKeys {
+		value, err := getValueForMetadataKey(user, key)
+		if err != nil {
+			return nil, err
+		}
+
+		if len(value) > 0 {
+			md = append(md, &command.AddMetadataEntry{
+				Key:   string(metadata.ScopeKey(ctx, key)),
+				Value: value,
+			})
+		}
+	}
+
+	return md, nil
+}
+
+func getValueForMetadataKey(user *ScimUser, key metadata.Key) ([]byte, error) {
+	value := getRawValueForMetadataKey(user, key)
+	if value == nil {
+		return nil, nil
+	}
+
+	switch key {
+	// json values
+	case metadata.KeyEntitlements:
+		fallthrough
+	case metadata.KeyIms:
+		fallthrough
+	case metadata.KeyPhotos:
+		fallthrough
+	case metadata.KeyAddresses:
+		fallthrough
+	case metadata.KeyRoles:
+		return json.Marshal(value)
+
+	// http url values
+	case metadata.KeyProfileUrl:
+		return []byte(value.(*schemas.HttpURL).String()), nil
+
+	// raw values
+	case metadata.KeyProvisioningDomain:
+		fallthrough
+	case metadata.KeyExternalId:
+		fallthrough
+	case metadata.KeyMiddleName:
+		fallthrough
+	case metadata.KeyHonorificSuffix:
+		fallthrough
+	case metadata.KeyHonorificPrefix:
+		fallthrough
+	case metadata.KeyTitle:
+		fallthrough
+	case metadata.KeyLocale:
+		fallthrough
+	case metadata.KeyTimezone:
+		valueStr := value.(string)
+		if valueStr == "" {
+			return nil, nil
+		}
+
+		return []byte(valueStr), validateValueForMetadataKey(valueStr, key)
+	}
+
+	logging.Panicf("Unknown metadata key %s", key)
+	return nil, nil
+}
+
+func validateValueForMetadataKey(v string, key metadata.Key) error {
+	//nolint:exhaustive
+	switch key {
+	case metadata.KeyLocale:
+		if _, err := language.Parse(v); err != nil {
+			return serrors.ThrowInvalidValue(zerrors.ThrowInvalidArgument(err, "SCIM-MD11", "Could not parse locale"))
+		}
+		return nil
+	case metadata.KeyTimezone:
+		if _, err := time.LoadLocation(v); err != nil {
+			return serrors.ThrowInvalidValue(zerrors.ThrowInvalidArgument(err, "SCIM-MD12", "Could not parse timezone"))
+		}
+
+		return nil
+	}
+
+	return nil
+}
+
+func getRawValueForMetadataKey(user *ScimUser, key metadata.Key) interface{} {
+	switch key {
+	case metadata.KeyIms:
+		return user.Ims
+	case metadata.KeyPhotos:
+		return user.Photos
+	case metadata.KeyAddresses:
+		return user.Addresses
+	case metadata.KeyEntitlements:
+		return user.Entitlements
+	case metadata.KeyRoles:
+		return user.Roles
+	case metadata.KeyMiddleName:
+		if user.Name == nil {
+			return ""
+		}
+		return user.Name.MiddleName
+	case metadata.KeyHonorificPrefix:
+		if user.Name == nil {
+			return ""
+		}
+		return user.Name.HonorificPrefix
+	case metadata.KeyHonorificSuffix:
+		if user.Name == nil {
+			return ""
+		}
+		return user.Name.HonorificSuffix
+	case metadata.KeyExternalId:
+		return user.ExternalID
+	case metadata.KeyProfileUrl:
+		return user.ProfileUrl
+	case metadata.KeyTitle:
+		return user.Title
+	case metadata.KeyLocale:
+		return user.Locale
+	case metadata.KeyTimezone:
+		return user.Timezone
+	case metadata.KeyProvisioningDomain:
+		break
+	}
+
+	logging.Panicf("Unknown or unsupported metadata key %s", key)
+	return nil
+}