Render sponsor button in extension header

[isidorn]

VS Code is adding sponsor support in the May milestone. More details here microsoft/vscode#107482

For this we will add a new sponsor field in the package.json of an extension.
It would be great if the marketplace could render a sponsor button in the marketplace header when the sponsor field is present in the package.json

For example it could look like this. But it should not be called "Github Sponsor", just "Sponsor".

fyi @anangaur @sandy081

[anupkmr03]

Changes are done and deployed to PPE.

[isidorn]

@anupkmr03 awesome thank you!