Perform encoding before bloom filters write out

When entropy of bloom filter is low say nearly all 0 or all 1, we may want to consider to use encoding to save space.

**Reporter**: [Junjie Chen](https://issues.apache.org/jira/secure/ViewProfile.jspa?name=junjie) / @chenjunjiedada

_{**Note**: *This issue was originally created as [PARQUET-1495](https://issues.apache.org/jira/browse/PARQUET-1495). Please see the [migration documentation](https://issues.apache.org/jira/browse/PARQUET-2502) for further details.*}

该 issue 没有指定文件、测试或入口点。首先定位 bloom filter 的写入路径和现有的编码相关测试，然后确定低熵过滤器的预期行为。完成这项工作需要达成一致的编码方案，并有测试覆盖来证明 bloom filter 能够被正确写入并读回。

由索引模型根据 Issue 内容生成。