feat: list users scim v2 endpoint (#9187)

# Which Problems Are Solved
- Adds support for the list users SCIM v2 endpoint

# How the Problems Are Solved
- Adds support for the list users SCIM v2 endpoints under `GET
/scim/v2/{orgID}/Users` and `POST /scim/v2/{orgID}/Users/.search`

# Additional Changes
- adds a new function `SearchUserMetadataForUsers` to the query layer to
query a metadata keyset for given user ids
- adds a new function `NewUserMetadataExistsQuery` to the query layer to
query a given metadata key value pair exists
- adds a new function `CountUsers` to the query layer to count users
without reading any rows
- handle `ErrorAlreadyExists` as scim errors `uniqueness`
- adds `NumberLessOrEqual` and `NumberGreaterOrEqual` query comparison
methods
- adds `BytesQuery` with `BytesEquals` and `BytesNotEquals` query
comparison methods

# Additional Context
Part of #8140
Supported fields for scim filters:
* `meta.created`
* `meta.lastModified`
* `id`
* `username`
* `name.familyName`
* `name.givenName`
* `emails` and `emails.value`
* `active` only eq and ne
* `externalId` only eq and ne

internal/query/user_metadata.go

@@ -24,6 +24,7 @@ type UserMetadataList struct {
 
 type UserMetadata struct {
 	CreationDate  time.Time `json:"creation_date,omitempty"`
+	UserID        string    `json:"-"`
 	ChangeDate    time.Time `json:"change_date,omitempty"`
 	ResourceOwner string    `json:"resource_owner,omitempty"`
 	Sequence      uint64    `json:"sequence,omitempty"`
@@ -107,6 +108,38 @@ func (q *Queries) GetUserMetadataByKey(ctx context.Context, shouldTriggerBulk bo
 	return metadata, err
 }
 
+func (q *Queries) SearchUserMetadataForUsers(ctx context.Context, shouldTriggerBulk bool, userIDs []string, queries *UserMetadataSearchQueries) (metadata *UserMetadataList, err error) {
+	ctx, span := tracing.NewSpan(ctx)
+	defer func() { span.EndWithError(err) }()
+
+	if shouldTriggerBulk {
+		_, traceSpan := tracing.NewNamedSpan(ctx, "TriggerUserMetadataProjection")
+		ctx, err = projection.UserMetadataProjection.Trigger(ctx, handler.WithAwaitRunning())
+		logging.OnError(err).Debug("trigger failed")
+		traceSpan.EndWithError(err)
+	}
+
+	query, scan := prepareUserMetadataListQuery(ctx, q.client)
+	eq := sq.Eq{
+		UserMetadataUserIDCol.identifier():     userIDs,
+		UserMetadataInstanceIDCol.identifier(): authz.GetInstance(ctx).InstanceID(),
+	}
+	stmt, args, err := queries.toQuery(query).Where(eq).ToSql()
+	if err != nil {
+		return nil, zerrors.ThrowInternal(err, "QUERY-Egbgd", "Errors.Query.SQLStatment")
+	}
+
+	err = q.client.QueryContext(ctx, func(rows *sql.Rows) error {
+		metadata, err = scan(rows)
+		return err
+	}, stmt, args...)
+	if err != nil {
+		return nil, err
+	}
+	metadata.State, err = q.latestState(ctx, userMetadataTable)
+	return metadata, err
+}
+
 func (q *Queries) SearchUserMetadata(ctx context.Context, shouldTriggerBulk bool, userID string, queries *UserMetadataSearchQueries, withOwnerRemoved bool) (metadata *UserMetadataList, err error) {
 	ctx, span := tracing.NewSpan(ctx)
 	defer func() { span.EndWithError(err) }()
@@ -164,6 +197,44 @@ func NewUserMetadataKeySearchQuery(value string, comparison TextComparison) (Sea
 	return NewTextQuery(UserMetadataKeyCol, value, comparison)
 }
 
+func NewUserMetadataExistsQuery(key string, value []byte, keyComparison TextComparison, valueComparison BytesComparison) (SearchQuery, error) {
+	// linking queries for the subselect
+	instanceQuery, err := NewColumnComparisonQuery(UserMetadataInstanceIDCol, UserInstanceIDCol, ColumnEquals)
+	if err != nil {
+		return nil, err
+	}
+
+	userIDQuery, err := NewColumnComparisonQuery(UserMetadataUserIDCol, UserIDCol, ColumnEquals)
+	if err != nil {
+		return nil, err
+	}
+
+	// text query to select data from the linked sub select
+	metadataKeyQuery, err := NewTextQuery(UserMetadataKeyCol, key, keyComparison)
+	if err != nil {
+		return nil, err
+	}
+
+	// text query to select data from the linked sub select
+	metadataValueQuery, err := NewBytesQuery(UserMetadataValueCol, value, valueComparison)
+	if err != nil {
+		return nil, err
+	}
+
+	// full definition of the sub select
+	subSelect, err := NewSubSelect(UserMetadataUserIDCol, []SearchQuery{instanceQuery, userIDQuery, metadataKeyQuery, metadataValueQuery})
+	if err != nil {
+		return nil, err
+	}
+
+	// "WHERE * IN (*)" query with subquery as list-data provider
+	return NewListQuery(
+		UserIDCol,
+		subSelect,
+		ListIn,
+	)
+}
+
 func prepareUserMetadataQuery(ctx context.Context, db prepareDatabase) (sq.SelectBuilder, func(*sql.Row) (*UserMetadata, error)) {
 	return sq.Select(
 			UserMetadataCreationDateCol.identifier(),
@@ -200,6 +271,7 @@ func prepareUserMetadataListQuery(ctx context.Context, db prepareDatabase) (sq.S
 	return sq.Select(
 			UserMetadataCreationDateCol.identifier(),
 			UserMetadataChangeDateCol.identifier(),
+			UserMetadataUserIDCol.identifier(),
 			UserMetadataResourceOwnerCol.identifier(),
 			UserMetadataSequenceCol.identifier(),
 			UserMetadataKeyCol.identifier(),
@@ -215,6 +287,7 @@ func prepareUserMetadataListQuery(ctx context.Context, db prepareDatabase) (sq.S
 				err := rows.Scan(
 					&m.CreationDate,
 					&m.ChangeDate,
+					&m.UserID,
 					&m.ResourceOwner,
 					&m.Sequence,
 					&m.Key,