1.add ding talk plugin - custom robot send group message

[673575554]

Describe what this PR does / why we need it

This pr focus on two things:
1.Added plugin to send ding talk custom robot message
2.Example verification

Does this pull request fix one issue?

#98

Describe how you did it

add dingtalk plugin

Describe how to verify it

The new example can verify it;

Special notes for reviews

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1 out of 2 committers have signed the CLA.

✅ 673575554
❌ YunLong

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