Don't write page level statistics

[asfimport]

Page level statistics are never used in production and after adding column indexes they are completely useless. Fortunately, statistics are optional in both the v1 and v2 pages therefore, we can safely stop writing them.

Reporter: Gabor Szadovszky / @gszadovszky
Assignee: Gabor Szadovszky / @gszadovszky

Related issues:

• Column indexes (is blocked by)

PRs and other links:

• GitHub Pull Request #549

_{Note: This issue was originally created as PARQUET-1365. Please see the migration documentation for further details.}