Feature: Kestrel MinRequestBodyDataRate configurability

Currently Azure Functions doesn't allow the Kestrel [MinRequestBodyDataRate](https://learn.microsoft.com/en-us/dotnet/api/microsoft.aspnetcore.server.kestrel.core.kestrelserverlimits.minrequestbodydatarate?view=aspnetcore-10.0) to be customized by the user. The Host uses the default 240 bytes/second rate with a 5 second grace period.

This works well for most scenarios, however there can be cases where customers have slow clients that exceed these limits, causing upload timeouts leading to failed requests. See ICM #51000001198359 for an example.

This issue tracks a _potential_ change we could make to allow this to be customized. There are no plans to do this at this time, but we'll leave this issue here to see if other customers require this. The expectation is that the default works for most customers.

Start by tracing how the Azure Functions Host configures Kestrel's MinRequestBodyDataRate and where user-facing settings are defined. Review the linked Kestrel documentation and the slow-client timeout scenario. Done would mean a considered customization path that preserves the current default behavior and is validated for upload requests.

Written by the indexing model from the issue text.