feat: persist shard to mysql

[simlecode]

关联的Issues (Related Issues)

#343

改动 (Proposed Changes)

shard 支持 MySQL 存储

附注 (Additional Info)

自查清单 (Checklist)

在你认为本 PR 满足被审阅的标准之前，需要确保 / Before you mark the PR ready for review, please make sure that:

• 符合Venus项目管理规范中关于PR的相关标准 / The PR follows the PR standards set out in the Venus project management guidelines
• 具有清晰明确的commit message / All commits have a clear commit message.
• 包含相关的的测试用例或者不需要新增测试用例 / This PR has tests for new functionality or change in behaviour or not need to add new tests.
• 包含相关的的指南以及文档或者不需要新增文档 / This PR has updated usage guidelines and documentation or not need
• 通过必要的检查项 / All checks are green

[codecov-commenter]

Codecov Report

Merging #354 (4cd6b86) into master (34a7277) will increase coverage by 0.05%.
The diff coverage is 33.04%.

❗ Your organization is not using the GitHub App Integration. As a result you may experience degraded service beginning May 15th. Please install the Github App Integration for your organization. Read more.

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #354      +/-   ##
==========================================
+ Coverage   20.81%   20.87%   +0.05%     
==========================================
  Files         190      191       +1     
  Lines       23086    23195     +109     
==========================================
+ Hits         4806     4842      +36     
- Misses      17501    17568      +67     
- Partials      779      785       +6     

Flag	Coverage Δ
unittests	20.87% <33.04%> (+0.05%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
config/config.go	0.00% <ø> (ø)
dagstore/wrapper.go	40.94% <0.00%> (-0.94%)	⬇️
models/module.go	0.00% <0.00%> (ø)
models/mysql/db.go	60.68% <0.00%> (-2.62%)	⬇️
dagstore/shard.go	38.94% <38.94%> (ø)
models/testing.go	63.26% <100.00%> (ø)

... and 1 file with indirect coverage changes