[MSHARED-650] Fire ExecutionEvent from DefaultMavenReportExecutor

**[Matt Nelson](https://issues.apache.org/jira/secure/ViewProfile.jspa?name=mattnelson)** opened **[MSHARED-650](https://issues.apache.org/jira/browse/MSHARED-650?redirect=false)** and commented

The event spy features added currently only support plugin mojos. When building site all the report mojos are grouped together under the site plugin and do not enable the ability to profile the site and find slow mojos. I dug through the code and it appears that the `DefaultMavenReportExecutor`[1] could be instrumented with the Catapult to fire events for each report mojo that the `EventSpy`[2] can handle.

[1] https://github.com/apache/maven-shared/blob/maven-reporting-exec-1.3/src/main/java/org/apache/maven/reporting/exec/DefaultMavenReportExecutor.java
[2] https://github.com/apache/maven/blob/maven-3.5.0/maven-core/src/main/java/org/apache/maven/eventspy/EventSpy.java

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**Issue Links:**
- [MNG-7479](https://issues.apache.org/jira/browse/MNG-7479) Export the package org.apache.maven.eventspy