[Umbrella] Implement PendingUpdate subclasses

[wgtmac]

This issue tracks the progress of implementation of PendingUpdate subclasses. To implement each subclass, we need to make sure that following goals are met:

1. Implement respective functions in the TableMetadataBuilder for this kind of update.
2. Implement respective TableUpdate subclass (if exists) to apply uncommitted changes to TableMetadataBuilder and generate update requirements.
3. Expose the new update as an interface to Table and Transaction classes.

Below is the list of subclasses that are expected to add. They should be put into the iceberg/update subdirectory.

Medadata Update:

Unlike Java, we don't need pure interface for these classes.

• UpdateProperties @WZhuo
• ReplaceSortOrder @HeartLinked
• UpdateSchema @gty404
• UpdatePartitionSpec @zhjwpku
• ManageSnapshots (<- SnapshotManager)
• SetSnapshot
• UpdateLocation (<- SetLocation)
• UpdatePartitionStatistics
• UpdateSnapshotReference
• UpdateStatistics
• ExpireSnapshots

Data Update:

For these classes, we still need intermediate interfaces and classes to consolidate common logic.

• SnapshotUpdate(SnapshotProducer) @zhjwpku
• FastAppend
• MergingSnapshotProducer
• OverwriteFiles
• RowDelta
• MergeAppend
• DeleteFiles
• RewriteFiles
• ReplacePartitions
• RewriteManifests
• CherryPickOperation

[shangxinli]

Make sense @wgtmac.