Add a UI element to make "attach" easier.

[ericsnowcurrently]

The experience of attaching the debugger to a running process is not great. (For that matter, neither is starting the process separately first...) It requires fiddling around in the launch config, which isn't an obvious step (at least not for newer VSC users).

When I tried attach I was expecting to find a UI element (e.g. button, command) that would trigger a dialog box where I would enter the info needed for attach. I found no such thing. Instead I had to figure out about the launch config and puzzle out what info I needed. Having the expected UI element would have improved my experience.

Environment data

• VS Code version: 1.22.1
• Extension version (available under the Extensions sidebar): 2018.3.1
• OS and version: Ubuntu 16.04
• Python version (& distribution if applicable, e.g. Anaconda): n/a
• Type of virtual environment used (N/A | venv | virtualenv | conda | ...): n/a
• Relevant/affected Python packages and their versions: n/a

Actual behavior

see above

Expected behavior

see above

Steps to reproduce:

1. start the process (separately)
2. open launch.json
3. find the appropriate launch config (default: "Python: Attach")
4. edit "host", "port", and "secret" (as appropriate)
5. start the debugger as normal

[DonJayamanne]

Closing this issue as we have separate issues to track each.

• Selecting a local process for debugging is tracked in Attach debugger to a local process #1078
• Improvements to remove debugging is tracked here Improve remote debugging setup #2493

@ericsnowcurrently
If #2493 does not address your concerns, then please update #2493 with your suggestions.