WIP: MergeTree Folders

[lmangani]

This WIP PR attempts implementing a discovery function to read data from ClickHouse generated MergeTree leveraging the columns.txt and count.txt files to read the data.bin values.

-rw-r--r-- 1 root root  259 Nov 19  2023 checksums.txt
-rw-r--r-- 1 root root   94 Nov 19  2023 columns.txt
-rw-r--r-- 1 root root    1 Nov 19  2023 count.txt
-rw-r--r-- 1 root root   92 Nov 19  2023 data.bin
-rw-r--r-- 1 root root   62 Nov 19  2023 data.cmrk3
-rw-r--r-- 1 root root   10 Nov 19  2023 default_compression_codec.txt
-rw-r--r-- 1 root root    1 Nov 19  2023 metadata_version.txt
-rw-r--r-- 1 root root   50 Nov 19  2023 primary.cidx
-rw-r--r-- 1 root root  229 Nov 19  2023 serialization.json

The function is not yet fully functional and has lots of casting issues but has potential:

D SELECT * FROM clickhouse_folder('/root/.chdb_data/data/a/test/all_1_1_0/');