feat: support get result set schema for python sdk

[tobegit3hub]

• Add util to convert int type to string type.
• Add util to get_resultset_schema in db api.
• Add API to get all databases and get tables from specified database.

[github-actions]

Linux Test Report

     50 files       91 suites   9m 13s ⏱️
4 218 tests 4 215 ✔️ 3 💤 0 ❌
4 247 runs  4 244 ✔️ 3 💤 0 ❌

Results for commit f1b3c67.

♻️ This comment has been updated with latest results.

[codecov]

Codecov Report

Merging #1194 (f1b3c67) into main (6786790) will not change coverage.
The diff coverage is n/a.

@@            Coverage Diff            @@
##               main    #1194   +/-   ##
=========================================
  Coverage     42.90%   42.90%           
  Complexity      279      279           
=========================================
  Files           562      562           
  Lines        106050   106050           
  Branches        985      985           
=========================================
  Hits          45503    45503           
  Misses        60364    60364           
  Partials        183      183           

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[HuilinWu2]

LGTM