Remove .vscode settings and add to gitignore (#1929)

.vscode's settings.json can get cluttered with installation-specific
settings, which can lead to confusing pull requests. Instead, let's use
the approach outlined here:

https://stackoverflow.com/a/48387809

This provides a set of defaults that people can use, which we can
extend over time.

.gitignore

@@ -4,6 +4,7 @@
 *.egg-info/
 .DS_Store
 .mypy_cache/
+.vscode/
 venv/
 target/
 

README.md

@@ -47,6 +47,12 @@ Optionally, download java dependencies
 mvn dependency:copy-dependencies
 ```
 
+Finally, if you are using Visual Studio Code, you may also wish to use our recommended defaults:
+
+```bash
+cp .vscode/settings.json.default .vscode/settings.json
+```
+
 And you should now be set up to start working in the repo! The easiest way to do this is for many tasks is to use `bqetl`, which is described below.