*: support lightning (#2051)

[ti-chi-bot]

This is an automated cherry-pick of #2051

Signed-off-by: Little-Wallace bupt2013211450@gmail.com

What problem does this PR solve?

I will use lightning import the full data produced by dumpling instead of loader. Lightning could import data much more quickly than loader.

What is changed and how it works?

User only need to set configure tidb.backend to local or tidb. Then DM-master will start a task in DM-worker with lightning.

Check List

Tests

• Unit test
• Manual test (add detailed scripts or steps below)

Code changes

• Has exported function/method change
• Has exported variable/fields change
• Has interface methods change
• Has persistent data change

Side effects

• Possible performance regression
• Increased code complexity
• Breaking backward compatibility

Related changes

• Need to cherry-pick to the release branch
• Need to update the documentation
• Need to update the dm/dm-ansible
• Need to be included in the release note

[ti-chi-bot]

[REVIEW NOTIFICATION]

This pull request has been approved by:

• Ehco1996
• lance6716

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[lance6716]

/merge

[ti-chi-bot]

This pull request has been accepted and is ready to merge.

Commit hash: f44282c64c643a06ed60cde0529f5f68b86a1df9

[ti-chi-bot]

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[lance6716]

/run-unit-tests