IGinX 0.7.0 -- Self-hosting high-performance storage engine!

NEWS:

1. 全面启动支持TPC测试！
2. 增加高性能集成存储引擎
3. 增加高效的开/闭源查询优化规则
4. 降采样语法调整
5. 更新开源协议：从Apache 2.0 到GPL-v3.0

What's Changed

• feat(optimizer): distinct eliminate rule by @Yihao-Xu in #343
• feat(query): adjust downsample query by @shinyano in #347
• ci: manually run full test suite by @aqni in #355
• feat(optimizer): Join Factorization Rule, Optimizer Independent and Confuse by @Yihao-Xu in #352
• feat(optimizer): Outer Join Eliminate Rule by @Yihao-Xu in #358
• feat(python): allow inserting dataframe by @shinyano in #357
• style: license changed from Apache 2.0 to GPL-3.0 by @zhuyuqing in #365
• feat(optimizer): coexist with extension by @aqni in #376
• feat(parquet): reimplement parquet buffer by @aqni in #373
• feat(test): tpc-h regression test by @jzl18thu in #372

Full Changelog: v0.6.0...v0.7.0