compact dlt pipeline state table in filesystem destination

[rudolfix]

Background
We started to store pipeline state and schemas in filesystem destination to be able to restore them. In case of state table each load may produce a new file. We should truncate old states ie. to just keep 100 newest.

Requirements

1. when load is completed, delete old files in the _dlt_pipeline_state table
2. keep N last state files
3. delete only the state files that corresponds to finished loads (they have corresponding completed entry). this is to prevent a rate case when we have 100 unsuccessful partial loads and we delete the last right state
4. make this mechanism on by default and allow it to be disabled with a flag