Enable setting custom jsHint library on project level setting

[ki82]

Today setting a custom jsHint library is only available using the workspace settings.

It would be very useful if it could be able to set this on a project level as well.

Our use case is that we would like all our developers to use a custom jsHint library and they only share project level metadata.

(I have also tried setting this using Workspace Mechanic but they don't support variables such as ${WORKSPACE_LOC}