node-stats/indices_stats: allow overriding the default list of sections

[dliappis]

Currently collecting indices_stats using the node-stats telemetry device, limits the collection to predefined list of objects that can't be overriden.

Introduce a new telemetry_params property for node-stats e.g. node-stats-indices-include-list allowing us to configure what gets collected.

A complete indices object retrieved from node-stats using the latest ES master:

indices

```json { "docs": { "count": 145552336, "deleted": 0 }, "store": { "size_in_bytes": 13020312961 }, "indexing": { "index_total": 145623107, "index_time_in_millis": 5051567, "index_current": 2, "index_failed": 0, "delete_total": 0, "delete_time_in_millis": 0, "delete_current": 0, "noop_update_total": 0, "is_throttled": false, "throttle_time_in_millis": 0 }, "get": { "total": 0, "time_in_millis": 0, "exists_total": 0, "exists_time_in_millis": 0, "missing_total": 0, "missing_time_in_millis": 0, "current": 0 }, "search": { "open_contexts": 0, "query_total": 0, "query_time_in_millis": 0, "query_current": 0, "fetch_total": 0, "fetch_time_in_millis": 0, "fetch_current": 0, "scroll_total": 0, "scroll_time_in_millis": 0, "scroll_current": 0, "suggest_total": 0, "suggest_time_in_millis": 0, "suggest_current": 0 }, "merges": { "current": 2, "current_docs": 20076614, "current_size_in_bytes": 1750311890, "total": 898, "total_time_in_millis": 3273951, "total_docs": 430367759, "total_size_in_bytes": 38671941092, "total_stopped_time_in_millis": 0, "total_throttled_time_in_millis": 1851101, "total_auto_throttle_in_bytes": 39040589 }, "refresh": { "total": 2026, "total_time_in_millis": 251158, "listeners": 0 }, "flush": { "total": 57, "periodic": 54, "total_time_in_millis": 166282 }, "warmer": { "current": 0, "total": 1964, "total_time_in_millis": 61 }, "query_cache": { "memory_size_in_bytes": 0, "total_count": 0, "hit_count": 0, "miss_count": 0, "cache_size": 0, "cache_count": 0, "evictions": 0 }, "fielddata": { "memory_size_in_bytes": 0, "evictions": 0 }, "completion": { "size_in_bytes": 0 }, "segments": { "count": 105, "memory_in_bytes": 56689173, "terms_memory_in_bytes": 48594746, "stored_fields_memory_in_bytes": 4622864, "term_vectors_memory_in_bytes": 0, "norms_memory_in_bytes": 6720, "points_memory_in_bytes": 3415991, "doc_values_memory_in_bytes": 48852, "index_writer_memory_in_bytes": 13356260, "version_map_memory_in_bytes": 0, "fixed_bit_set_memory_in_bytes": 0, "max_unsafe_auto_id_timestamp": -1, "file_sizes": {} }, "translog": { "operations": 8557944, "size_in_bytes": 1746498136, "uncommitted_operations": 2561416, "uncommitted_size_in_bytes": 525690708, "earliest_last_modified_age": 0 }, "request_cache": { "memory_size_in_bytes": 0, "evictions": 0, "hit_count": 0, "miss_count": 0 }, "recovery": { "current_as_source": 0, "current_as_target": 0, "throttle_time_in_millis": 0 } } ```

[dliappis]

Closed by https://github.com/elastic/rally/pull/589