log-backup: using streaming to load metadata for preventing OOM

[YuJuncen]

What problem does this PR solve?

Issue Number: close #38404

Problem Summary:
This PR make the restore procedure load the metadata lazily.

What is changed and how it works?

This PR has introduced a new package iter, which provides the impure iterator type TryNextor.

Then the restore procedure is someway rewritten, to allow the restoration of data files become pipelined.

For better testing and isolate the code using generics, this PR also extracted the file read part from the restore.Client to restore.logFileManager.

Test Result

- master -	- This PR -

Check List

Tests

• Unit test
• Integration test
• Manual test (add detailed scripts or steps below)
• No code

Side effects

• Performance regression: Consumes more CPU

Release note

Please refer to Release Notes Language Style Guide to write a quality release note.

Reduced the memory peak memory usage.

[ti-chi-bot]

[REVIEW NOTIFICATION]

This pull request has been approved by:

• Leavrth
• joccau

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[YuJuncen]

🤔 concurrentddltest_test
/run-unit-test

[joccau]

LGTM

[YuJuncen]

/merge

[ti-chi-bot]

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

Commit hash: 547d879