Remove thread count limitation on workers

[brettsam]

Discussion for #1962

[brettsam]

Notes

• Requires that the Python worker can determine what the host version is: Host should pass capabilities (or version) to workers on startup azure-functions-host#7549.
• Desirable for dynamic concurrency to be working for this, but not required.
• Some risk that customers will hit out-of-memory errors.
• But the tradeoff in default performance is desired.

[paulbatum]

We might need an out-of-memory python detector that recommends tweaking this setting

[AnatoliB]

And one for PowerShell as well

[AnatoliB]

For more details on the motivation, see OOP Concurrency Throttling