derived_data_metrics_tailer: split metrics by deriving process

Summary:
We would like to have a better understanding of which process is deriving commits.  This will let us improve our headline metrics to exclude background processes like backfilling.

We add the concept of a "deriver", which is a category of binary (determined by build rule) that performs derivation.  We split the ODS metric into subcategories.

For seamless migration, we log an aggregate stat also.

Reviewed By: mitrandir77

Differential Revision: D65839025

fbshipit-source-id: 08f584b8adab282f3d47de7fe0826b5f95f115b2

eden/mononoke/tools/facebook/derived_data_metrics_tailer/TARGETS

@@ -12,6 +12,7 @@ rust_binary(
     deps = [
         "fbsource//third-party/rust:anyhow",
         "fbsource//third-party/rust:clap",
+        "fbsource//third-party/rust:enum-map",
         "fbsource//third-party/rust:faster-hex",
         "fbsource//third-party/rust:futures",
         "fbsource//third-party/rust:lru",