Productise "debug target ready" hook for launch configs

[weinand]

See #69311

[weinand]

the limitations of the preview have been addressed as follows:

• the pattern is now matched in the integrated terminal as well.
• if the action debugWithChrome is used, and the Debugger for Chrome is not installed, a proper warning is shown.
• other browser based debuggers will be supported at a future point in time if enough users are asking for it.