Streamable CWL graph images

[stain]

Description

Provide InputStream and Path based methods for returning from GraphService, instead of the oldie File using temporary files.

Motivation and Context

The current implementation has excessive use of temporary files.

This patch will improve #239 by avoiding it making temporary files just to call the methods or return images over HTTP.

How Has This Been Tested?

CWLServiceTest and GraphVizServiceTest have been updated.

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have added tests to cover my changes.
• All new and existing tests passed.

[lgtm-com]

This pull request introduces 2 alerts when merging f36ef42 into 3a5c2d0 - view on LGTM.com

new alerts:

• 2 for Spurious Javadoc @param tags