[GEO] OOM Error when using QuadPrefixTree with 1m precision

[nknize]

Fixing issue #9691 revealed a deeper problem with the QuadPrefixTree's memory usage. At 1m precision the example shape in https://gist.github.com/nknize/abbcb87f091b891f85e1 consumes more than 1GB of memory. This is initially alleviated by using 2 bit encoded quads (instead of 1byte) but only delays the problem. Moreover, as new complex shapes are added duplicate quadcells are created - thus introducing unnecessary redundant memory consumption (an inverted index approach makes mosts sense - its Lucene!).

For now, if a QuadTree is used for complex shapes great care must be taken and precision must be sacrificed (something that's automatically done with the distance_error_pct without the user knowing - which is a TERRIBLE approach). An alternative improvement could be to apply a Hilbert R-Tree - which will be explored as a separate issue. Or to restrict the accuracy to a lower level of precision (something that's undergoing experimentation).