WT-8712 adds the function to obtain an object list given a bucket. Use that function to implement S3's directory listing, i.e. the following functions:

• WT_FILE_SYSTEM.fs_directory_list
• WT_FILE_SYSTEM.fs_directory_list_single
• WT_FILE_SYSTEM.fs_directory_list_free

Among things to consider:

• Only return the objects that match the prefix
• Take care of freeing the list
• Avoid code duplication between directory_list an directory_list_single
• Add relevant testing to the s3_store python test - following test_tiered06.py
• Add relevant statistics (No longer required - stats will be take care of by WT-8761)