Add InstrumentationScope/Logger Name to log data model (#2359)

Contributes to open-telemetry/opentelemetry-specification#1215
Contributes to open-telemetry/opentelemetry-specification#2358

The topics has been discussed at length.

This [PR](open-telemetry/opentelemetry-specification#2276) made
possible to record instrumentation scope for traces and metrics. The intent is also to
have instrumentation scope part of log data model and where available record logger name
as the instrumentation scope name.

specification/logs/data-model.md

@@ -30,6 +30,7 @@
     + [Comparing Severity](#comparing-severity)
   * [Field: `Body`](#field-body)
   * [Field: `Resource`](#field-resource)
+  * [Field: `InstrumentationScope`](#field-instrumentationscope)
   * [Field: `Attributes`](#field-attributes)
     + [Errors and Exceptions](#errors-and-exceptions)
 - [Example Log Records](#example-log-records)
@@ -194,6 +195,7 @@ SeverityText   |The severity text (also known as log level).
 SeverityNumber |Numerical value of the severity.
 Body           |The body of the log record.
 Resource       |Describes the source of the log.
+InstrumentationScope|Describes the scope that emitted the log.
 Attributes     |Additional information about the event.
 
 Below is the detailed description of each field.
@@ -436,6 +438,20 @@ from the same source. SHOULD follow OpenTelemetry
 [semantic conventions for Resources](../resource/semantic_conventions/README.md).
 This field is optional.
 
+### Field: `InstrumentationScope`
+
+Type: (Name,Version) tuple of strings.
+
+Description: the [instrumentation scope](../glossary.md#instrumentation-scope).
+Multiple occurrences of events coming from the same scope can happen across time and
+they all have the same value of `InstrumentationScope`. For log sources which define
+a logger name (e.g. Java
+[Logger Name](https://docs.oracle.com/javase/7/docs/api/java/util/logging/Logger.html#getLogger(java.lang.String)))
+the Logger Name SHOULD be recorded as the Instrumentation Scope name.
+
+Version is optional. Name SHOULD be specified if version is specified, otherwise Name
+is optional.
+
 ### Field: `Attributes`
 
 Type: `map<string, any>`.