trim whitespace from project variables

Description

Whitespace characters are not trimmed or linted from a project's variables. This makes it easy for someone (such as I) to accidentally have a whitespace in the variable value and then spend a bunch of time trying to debug the build. Obliviously, a user error situation but easy to help users (such as I) not make these kind of errors :D.

Proposal

I think it would be legitimate just to trim the whitespace prior to saving the variable. If there are concerns about modifying hte user input, then I think we should use client side validation to detect the proceeding and trailing white space, inform the user and ask if they want to correct or submit anyway.