Log CultureInfo on Host startup

The AzureFunctions host should be able to run under a different culture to that for the host operating system and by default run under the en-US culture so to avoid any culture related development issues.

It would also be good to display the configured/default culture at runtime for local debugging.

Start at Azure Functions host startup and the runtime logging used during local debugging; no specific files or tests are identified in the issue. Determine where the host culture is configured and where startup details are logged, then verify that the configured or default en-US culture is shown at runtime and used independently of the operating system culture.

Written by the indexing model from the issue text.