[feature] VSCode Debugging should start ROSCore if not running

[ooeygui]

what is needed
If ROSCore is not started when VSCode launch debugging is executed, you'll only get a small debug notification and the app doesn't launch.

why is it needed
This is different than ROSLaunch on the command line and leads to an extra step during debug sessions.

[anton-matosov]

+1
I got caught into this many many times in just a single day.
There are 2 possible ways to implement this:

1. Run roscore alongside other ros nodes and have debugger attached to it. That way when you terminate debug session, ros core will also terminate
2. Run a "start ros core" command of the extension. That way roscore will be started and managed by extension and will keep running until you stop it.

I am fairly new to ROS and vscode-ros extension and not sure which approach would be the best here.

[ooeygui]

Completed in 0.6.9