Allow Splitting GraphiteMergeTree Rollup Rules for Metrics

Why it matters

This feature allows users to define separate rollup rules for plain and tagged metrics within GraphiteMergeTree tables, improving flexibility and control over how metrics are aggregated and stored. It addresses the need to handle these metric types distinctly in rollup processing.

How to use it

To use this feature, add the optional rule_type field to your rollup rules configuration in GraphiteMergeTree tables. Specify the appropriate metric type (plain or tagged) for each rule to apply different rollups accordingly.