Unpublish extension once Granite.Code extension is released

[fbricon]

• Change id (granite-code) and name (Granite.Code) in package.json, all *.md documentation
• Change id and name in constants, all labels across the extension
• Update icon
• Unpublish redhat.vscode-paver in Visual Studio Marketplace
• Unpublish redhat.vscode-paver in Open VSX (open a ticket, similar to Need to unpublish redhat.vscode-granite eclipse-openvsx/openvsx#1024)

[owtaylor]

Changing this to only track unpublishing the existing extension, since the new extension will be released from https://github.com/Granite-Code/granite-code/