Update profiler docs for capturing tiledb stats

[atolopko-czi]

Update profiler README to indicate that tiledb stats should be enabled, dumped, etc. via tiledbsoma.tiledbsoma_stats_*() methods. As all tiledb operations will eventually be performed via the core tiledb library, this will be the correct way to capture stats. Currently, tiledb stats are collected independently for both tiledb-py and tiledb core lib (C++).

This is a follow-up to single-cell-data/SOMA#162 (comment).