Update vulnerable dependencies (#401)

Fix parsing of --manifest-js command line argument (#374)

Add feature to support more advanced manifest specifications (#342)

Remove support for publisher creation from TFX. The API backing this functionality is being removed.

Restores missing error-handling code in the tfx login command.

Gets rid of the login error: TypeError: Cannot read property 'success' of undefined

• Add default contentType for .html files
• Fix default categories for tfx extension init. It is now an array of every possible category. End users can trim as needed.

Mostly dependency updates to resolve known security issues.

Updates REST API and fixes a few issues:

• Validation for "public" in manifest
• Fix tfx extension install issues
• Avoid connecting to the internet when running --help

Now we just require that you have at least 1 category, but we don't pre-validate that the category values are valid. This check will still be done on the server.

Other minor fixes, including changing branding from VSTS to Azure DevOps.