Support displaying inline values in VS Code

[luabud]

This has been added to version 1.56: https://code.visualstudio.com/updates/v1_56#_inline-values-by-default-for-some-languages

[fabioz]

@luabud @karthiknadig @int19h

I took a quick look at this and apparently this is a vscode-only feature (i.e.: not really debug-adapter related) and must be implemented in vscode-python by providing an vscode.InlineValuesProvider implementation, so, I think this request should be moved there.

[gregegg]

+1 -- this would be great to have.

[luabud]

@paulacamargo25 does it make sense to transfer this to vscode-python-debugger?