added function to server side dump dot for pipeline and media elements

[slabajo]

What is the current behavior you want to change?

provide additional debug tools, specifically a better dump dot function than the one already included. The point is that previous function gets limited by the transport to some maximum size in length. In some real pipelines this is not practical. So this funciton allows the server to write the dump dot files directly in theserver filesystem without limitations

What is the new behavior provided by this change?

Adding some API to the interface that allows trigerring generatng a dot file in the server side.

How has this been tested?

New test on the repository

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature / enhancement (non-breaking change which improves the project)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• My change requires a change to the documentation
• My change requires a change in other repository

Checklist

• I have read the Contribution Guidelines
• I have added an explanation of what the changes do and why they should be included
• I have written new tests for the changes, as applicable, and have successfully run them locally