add optional configuration for prometheus exporter (#3777)

## Changes

The suffix for types and units can be optionally disabled in Prometheus
exporters. This PR captures these configuration options to allow them to
then be captured by the OpenTelemetry Configuration as well.

* [x] Related issues
open-telemetry/opentelemetry-configuration#59

Author: Alex Boten

CHANGELOG.md

@@ -48,6 +48,8 @@ release.
   ([#3761](https://github.com/open-telemetry/opentelemetry-specification/pull/3761))
 - Clarifications and flexibility in Exemplar speicification.
   ([#3760](https://github.com/open-telemetry/opentelemetry-specification/pull/3760))
+- Add optional configuration for Prometheus exporters to optionally remove unit and type suffixes
+  ([#3777](https://github.com/open-telemetry/opentelemetry-specification/pull/3777))
 
 ### Logs
 

specification/metrics/sdk_exporters/prometheus.md

@@ -31,3 +31,9 @@ By default, it MUST NOT add any resource attributes as metric attributes.
 The configuration SHOULD allow the user to select which resource attributes to copy (e.g.
 include / exclude or regular expression based). Copied Resource attributes MUST NOT be
 excluded from target_info.
+
+A Prometheus Exporter MAY support a configuration option to produce metrics without a [unit suffix](../../compatibility/prometheus_and_openmetrics.md#metric-metadata)
+or UNIT metadata. The option MAY be named `without_units`, and MUST be `false` by default.
+
+A Prometheus Exporter MAY support a configuration option to produce metrics without a [type suffix](../../compatibility/prometheus_and_openmetrics.md#metric-metadata).
+The option MAY be named `without_type_suffix`, and MUST be `false` by default.