tsi index add useful statistic

### Feature Request

__Proposal:
- we use tsi1 as our metric index, however tsi index lack of statistics, may be tsl size, compact time, tsi memory size and so on

__Current behavior:
- tsi, partition, log_file lack of statistics

__Desired behavior:
- add statistics for tsi and tsi partition, help for trouble shotting

__Use case:
- help us find tsi memory too high problem

Begin by locating the TSI index and partition implementations and reviewing how existing index statistics are exposed. Define the required TSI and partition statistics, including size, compaction time, and memory usage, then add coverage showing they support diagnosing high TSI memory.

Written by the indexing model from the issue text.