Add RH auth extension recommendation

[cidrblock]

• Update the extension list to include RH auth
• Set the recommended extensions as shared constant
• Promote the vscode files to a common resource
• Share a list of common resources between project types
• Move the list of recommended extensions to a constant
• template data is now a dataclass to better track the vars needed for templating, convert to dict at the last minute when handing off to jinja
• Add a new json filter for jinja
• Add some tests for the json jinja filter