Added the cursor, garbage collector metrics along with additional memory metrics in "info search" to align redisearch

[Shivshankar-Reddy]

Added empty values to align with redisearch "info serch" output to make sure applications or client which retrive those value would not break. Once mechanism implemented the real time values can be updated.

here are the output after the changes.

127.0.0.1:6379> info search
# search_cursors
search_global_idle_internal:0
search_global_idle_user:0
search_global_total_internal:0
search_global_total_user:0

# search_garbage_collector
search_gc_bytes_collected:0
search_gc_marked_deleted_vectors:0
search_gc_total_cycles:0
search_gc_total_docs_not_collected:0
search_gc_total_ms_run:0

# search_hnswlib
search_hnsw_add_exceptions_count:0
search_hnsw_create_exceptions_count:0
search_hnsw_modify_exceptions_count:0
search_hnsw_remove_exceptions_count:0
search_hnsw_search_exceptions_count:0

# search_index_stats
search_number_of_attributes:0
search_number_of_indexes:0
search_total_indexed_documents:0

# search_indexing
search_background_indexing_status:NO_ACTIVITY

# search_memory
search_index_reclaimable_memory:0
search_largest_memory_index:0
search_largest_memory_index_human:0
search_smallest_memory_index:0
search_smallest_memory_index_human:0
search_used_memory_bytes:18480
search_used_memory_human:18.05KiB
search_used_memory_indexes:0
search_used_memory_indexes_human:0
search_used_memory_vector_index:0

# search_query
search_failure_requests_count:0
search_hybrid_requests_count:0
search_inline_filtering_requests_count:0
search_query_prefiltering_requests_cnt:0
search_result_record_dropped_count:0
search_successful_requests_count:0

# search_rdb
search_rdb_load_failure_cnt:0
search_rdb_load_success_cnt:0
search_rdb_save_failure_cnt:0
search_rdb_save_success_cnt:0

# search_string_interning
search_string_interning_store_size:0

# search_thread-pool
search_query_queue_size:0
search_reader_resumed_cnt:0
search_used_read_cpu:0
search_used_write_cpu:0
search_worker_pool_suspend_cnt:0
search_writer_queue_size:0
search_writer_resumed_cnt:0
search_writer_suspension_expired_cnt:0

# search_vector_externing
search_vector_externing_deferred_entry_cnt:0
search_vector_externing_entry_count:0
search_vector_externing_generated_value_cnt:0
search_vector_externing_hash_extern_errors:0
search_vector_externing_lru_promote_cnt:0
search_vector_externing_num_lru_entries:0
127.0.0.1:6379>