### What problem does this PR solve?
_Briefly describe what this PR aims to solve. Include background context
that will help reviewers understand the purpose of the PR._
Added the function of sending emails through SMTP
Instructions for use-
Corresponding parameters need to be configured
Need to output upstream in a fixed format
### Type of change
- [√] New Feature (non-breaking change which adds functionality)
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Co-authored-by: Kevin Hu <kevinhu.sh@gmail.com>
小黑马