Restart append data to probe

Summary

When restarting a simulation, the output is not properly appended to the probe H5 file.

Steps to reproduce

Restart a cyclotron simulation having a probe element.

What is the current bug behavior?

It overwrites the H5 file.

What is the expected correct behavior?

It appends the new turns to the H5 file leaving the previous steps untouched.

Possible fixes

Several possible fixes:

Set the OpalData::OPENMODE to APPEND in TrackRun if opal->inRestartRun() == True
Extend if-clause with || OpalData::getInstance()->inRestartRun() at line 224 of PluginElement::save().