HDDS-10007. Rename ManagedSstFileReader in rocksdb-checkpoint-differ

[adoroszlai]

What changes were proposed in this pull request?

Rename ManagedSstFileReader in rocksdb-checkpoint-differ to avoid confusion with the "real" ManagedSstFileReader from hdds-managed-rocksdb.

ozone/hadoop-hdds/managed-rocksdb/src/main/java/org/apache/hadoop/hdds/utils/db/managed/ManagedSstFileReader.java

Lines 23 to 26 in f9167a3

	/**
	* Managed SstFileReader.
	*/
	public class ManagedSstFileReader extends ManagedObject<SstFileReader> {

ozone/hadoop-hdds/rocksdb-checkpoint-differ/src/main/java/org/apache/ozone/rocksdb/util/ManagedSstFileReader.java

Lines 48 to 52 in f9167a3

	/**
	* ManagedSstFileReader provides an abstraction layer using which we can
	* iterate over multiple underlying SST files transparently.
	*/
	public class ManagedSstFileReader {

I think SstFileSetReader would be a better name.

https://issues.apache.org/jira/browse/HDDS-10007

How was this patch tested?

CI:
https://github.com/adoroszlai/ozone/actions/runs/7309005071

[swamirishi]

Thanks for the patch @adoroszlai . Changes look good to me

[adoroszlai]

Thanks @swamirishi for the review.