added start Ollama button and it functionality

[msivasubramaniaan]

This PR shows Start Ollama button when Ollama server was stopped. When user clicks the button it starts the server on terminal

[fbricon]

@msivasubramaniaan can you fix the conflicts please

[msivasubramaniaan]

@msivasubramaniaan can you fix the conflicts please

Done

[fbricon]

So I like the idea, but I'm not fond of the current implementation:
The command spawns a process that will die when closing vscode, it might be a good, or a bad thing. But I tend to prefer starting a service/daemon instead.

The problem with starting ollama as a daemon is, there's no universal way to do it:

• on Mac, running "ollama list" works (this is what is done after the brew installation)
• on Linux, the "ollama list" trick doesn't work, so you need to try starting the ollama service first, then fall back to launching ollama serve in the background. See the ollama_start.sh script called on linux after installation
• on Windows, I don't recall if the "ollama list" trick works. If it doesn't, we'd need to find a way to start the ollama service, and fall back to something like ollama serve >nul 2>&1

[fbricon]

no merge commits please, use rebase instead