Add debugging instructions

[zaaath]

This adds instructions on how to set up debugging environment in VS Code for both, the engine and the sql client. Debugging specific tests works great as well.

Context: when I first started working my way through the toydb codebase, it was hard to understand what's going on (even though the docs, the tests, and the code itself are beautifully written!) without a debugger, and I couldn't find instructions on how to debug the code in the repo itself. I ended up googling around and setting up debugging environments on two laptops. With this PR I want to make it easier for the new engineers to onboard.

[zaaath]

@erikgrinaker is there something missing in this PR? what is the next step to get this approved?

[erikgrinaker]

Hey @leotoff! Thanks for the PR, and sorry for the late reply -- it's been a busy week. I'll get back to you in a bit.

[erikgrinaker]

PS: please wrap lines at 100 chars, for consistency.

[zaaath]

Sorry about the delay, I'm working on addressing outstanding issues.

Tasks:

• [x] Get directions and then execute them for /var/lib/toydb -> ./data change in config/toydb.yaml
• [x] Generalize the process clean up step (Activity Monitor shouldn't be used)
• [x] Wrap lines at 100 chars

[erikgrinaker]

Whoops, totally forgot about this. Thanks again!