[spark] Add purge table command to clear data

[xuzifu666]

Purpose

Linked issue: close #xxx
Currently Paimon cannot clear data from table rightly, truncate would do a overwrite snapshot and clear data\manifest... after snapshot expire, but user sometime need clear data quickly to reduce storage pressure, so add a purge command to clear data quickly.

Tests

PaimonPurgeTableTestBase

API and Format

Documentation

[JingsongLi]

Can you find some similar examples? For example, from other lake formats

[xuzifu666]

Can you find some similar examples? For example, from other lake formats

Hudi truncate table would clear metadata and data directly； iceberg would do like paimon. In some env user want to delete all data quickly only need keep schema info, so add the command. @JingsongLi

[JingsongLi]

After offline discussing with @xuzifu666 , we can provide a procedure: purge_files.

[xuzifu666]

link this pr to: #4717 and close it first.