Automatically update ollama as part of install flow

[jamescho72]

Description:
During installation if a newer version of ollama is available get user confirmation and update in process.
For all supported platforms Mac, Linux, Windows.

[chetan-hireholi]

Hi, @jamescho72 thank you for your feedback! Do you mean, the 'install flow' of ollama? or install flow of Granite.Code extension on VSCode? If it is the latter, do you think it would be helpful if Granite.Code chat window suggests the user something like - "A new version on Ollama is available, to update Ollama, head towards the terminal and update Ollama....."

Since both components - Ollama and Gratnite.Code are separate individual component, we could only display a message for the user to take further actions.