Reduce support cases: File load timeout

[This log](https://github.com/Azure/azure-functions-nodejs-worker/pull/660) for [WEBSITE_RUN_FROM_PACKAGE](https://learn.microsoft.com/en-us/azure/azure-functions/run-functions-from-deployment-package) is definitely helping, although I'm not sure how visible it is to users.

One side note with run from package is that some users write files to their app dir (`/home/site/wwwroot`) and thus feel like they can't use run from package because it makes the dir read-only. We need to provide alternative behaviors because we don't want people writing to their app dir.

## Support cases from June 2023 - Sept 2023

_Internal-only links_:

- https://elixir.microsoft.com/case-review/2308090050004190
- https://elixir.microsoft.com/case-review/2302090020001746
- https://elixir.microsoft.com/case-review/2306280060001484
- https://elixir.microsoft.com/case-review/2306260030003837

Trying to write to `/home/site/wwwroot`:
- https://elixir.microsoft.com/case-review/2307250040012116