Add git filter for selected lines in vscode config json

[Flova]

Summary

The VS Code ROS extension always adds a bunch of user specific absolute paths to the vscode settings json. This results in every user having uncommitted changes by default. Accidentally committing them is also annoying. We therefore add a rule to git that ignores said files.

Proposed changes

• Add .gitattributes file that applies a custom filter on the settings file
• Add a custom filter rule that deletes lines containing absolute home directory paths from the given file.
• Install the custom filter with update make targets
• Also remove ros.rosSetupScript key from config as the extension did not work properly when is contained env variables, this was not an issue with previous versions of vscode. But it somehow discovers it without it in my version so I guess removing it is fine. Needs testing on other machine tho..