MM-11029 Adding plugin logging functionality. (#9034)

* Capturing stdout, stderr of plugins in logs.

* Cleanup go-plugin debug logs.

* Adding logging to plugin API

* Generating mocks.

* godoc convention

plugin/plugintest/hooks.go

@@ -1,4 +1,4 @@
-// Code generated by mockery v1.0.0
+// Code generated by mockery v1.0.0. DO NOT EDIT.
 
 // Regenerate this file using `make plugin-mocks`.