Use isolated as default --functions-worker project option in Azure Functions project templates

[stijnmoreels]

Is your feature request related to a problem? Please describe.
.NET 6 will be the last version where the in-process Azure Functions are not deprecated. We already have moved almost all our Azure Functions project templates toward isolated functions worker, but we currently still use in-process as our default.

Describe the solution you'd like
Set isolated as default --functions-worker project option in the Azure Functions project templates.

Additional context
Roadmap: https://techcommunity.microsoft.com/t5/apps-on-azure-blog/net-on-azure-functions-roadmap/ba-p/2197916