Add font and icon support to webview

[calebjacob]

Our NEAR Discovery Viewer recently provided two global assets to all components:

• Mona Sans font: https://github.com/near/near-discovery/blob/main/src/index.css#L1-L7
• Phosphor Icons: https://github.com/near/near-discovery/blob/main/src/App.js#L178-L180

These assets aren't available in the VS Code preview panel, so the fonts and icons won't render. The easiest thing to do would be to apply the same changes to your webview app:

near/near-discovery@f7a1537
near/near-discovery@2a5c22c

I'm not sure if there's a smarter way we can keep these in sync for the future.

[gagdiez]

This would be a simple change in how the components are displayed right? moreover, a change that will not be reflected in other gateways, but only the one at near.org.

Maybe it is ok if the vscode extension is gateway agnostic.