Scan operation including two steps:

1. Generate scan range list. Each scan range is a basic scheduling unit. For OlapScanNode, a scan range is a tablet. For ExternalFileScanNode, it is one or several blocks of a file.
2. Assign a BE for each scan range to execute.

This PR does two things:

1. Define the data structure for ScanNode scan range (ScanRangeList) and the interface in ScanNode to get it.
2. Implement the scan range generation logic and BE assign logic for ExternalFileScanNode. (ExternalFileScanNode is used by Hive, Iceberg, TVF query, broker load and stream load)

Checklist(Required)

• Does it affect the original behavior
• Has unit tests been added
• Has document been added or modified
• Does it need to update dependencies
• Is this PR support rollback (If NO, please explain WHY)

Further comments

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