Purpose

Enables drag & drop file feature on Start page as described in this jira task: https://jira.autodesk.com/browse/DYN-5738

• The user Drag & Drop a .dyn or .dyf file into Dynamo
• *.dyn or *.dyf extension constraint, other type of file would not work
• To the StartPage or another part that means an initial state, Dynamo will open the file

Declarations

Check these if you believe they are true

• The codebase is in a better state after this PR
• Is documented according to the standards
• The level of testing this PR includes is appropriate
• User facing strings, if any, are extracted into *.resx files
• All tests pass using the self-service CI.
• Snapshot of UI changes, if any.
• Changes to the API follow Semantic Versioning and are documented in the API Changes document.
• This PR modifies some build requirements and the readme is updated
• This PR contains no files larger than 50 MB

Release Notes

• implemented drag and drop behavior for .dyn and .dyf files
• added test for the new feature. the test is passing, but ignored as webView2 initialization still causes time out on master-15

Reviewers

@QilongTang

FYIs

@Amoursol