(UX) Better handling of errors and notifications

**Repro steps:**

1. don't have .NET installed
2. open notebook that uses .NET kernels
3. :bug: see errors

It seems like the extension should better handle errors and not just print them into the notification. Also, there are way too many buttons on here which make it hard to read and figure out which actions does what. Lastly, the contrast on the status bar item is poor and should properly use the [error status bar](https://code.visualstudio.com/api/references/extension-guidelines#error-status-bar-item) item instead.

**Extension Version:** 1.0.0
**Error Message:** .NET Acquisition Failed: Installation failed: Error: Command failed: "/Users/anonymous/.vscode-insiders/extensions/ms-dotnettools.vscode-dotnet-runtime-1.5.0/dist/install scripts/dotnet-install.sh" -InstallDir "/Users/anonymous/Library/Application Support/Code - Insiders/User/globalStorage/ms-dotnettools.vscode-dotnet-runtime/.dotnet/5.0.15" -Version 5.0.15 -Runtime dotnet
dotnet_install: Error: Could not find `.NET Core Runtime` with version = 5.0.15
dotnet_install: Error: Refer to: https://aka.ms/dotnet-os-lifecycle for information on .NET Core support

**Error Stack:** Error: .NET Acquisition Failed: Installation failed: Error: Command failed: "/Users/anonymous/.vscode-insiders/extensions/ms-dotnettools.vscode-dotnet-runtime-1.5.0/dist/install scripts/dotnet-install.sh" -InstallDir "/Users/anonymous/Library/Application Support/Code - Insiders/User/globalStorage/ms-dotnettools.vscode-dotnet-runtime/.dotnet/5.0.15" -Version 5.0.15 -Runtime dotnet
dotnet_install: Error: Could not find `.NET Core Runtime` with version = 5.0.15
dotnet_install: Error: Refer to: https://aka.ms/dotnet-os-lifecycle for information on .NET Core support

at /Users/anonymous/.vscode-insiders/extensions/vscode-dotnet-runtime-library/dist/Acquisition/DotnetCoreAcquisitionWorker.js:89:27