Filter to interesting processes in process picker

[connor4312]

microsoft/vscode#169033

We can probably elminate certain tools, like nodemon, and/or just sort processes that start from node_modules lower than ones that don't. It's still desirable in some cases, like mocha, so we don't want to remove them entirely.

[snotmare]

One possible way to handle this would be to add a filter property in launch.json that allows regex to determine what processes are shown. This would add some flexibility for various scenarios.