* move GROUP_CONCAT/JSON_ARRAYAGG storage to the RowGroup from
the RowAggregation*
* internal data structures (de)serialization
* get rid of a specialized classes for processing JSON_ARRAYAGG
* move the memory accounting to disk-based aggregation classes
* allow aggregation generations to be used for queries with
GROUP_CONCAT/JSON_ARRAYAGG
* Remove the thread id from the error message as it interferes with the mtr
* toCppCode for ParseTree and TreeNode
* generated tree is compiling
* Put tree constructors into tests
* Minor fixes
* Fixed parse + some constructors
* Fixed includes, removed debug and old data
* Hopefully fix clang errors
* Forgot an override
* More overrides
