Migrate existing Grunt tasks to Gulp

[paglias]

Gulp is better and also we don't like having 2 build tools

Want to back this issue? Post a bounty on it! We accept bounties via Bountysource.

[noppanit]

I think it's a great idea. Anybody pick this up? May I?

[crookedneighbor]

@noppanit Go for it. I'll be happy to review it.

[librarianmage]

Is this still a thing?

[Alys]

It's still desirable and no current work is being done on it.

In #6112 (comment), @crookedneighbor says:
"Let's do smaller PRs extracting one grunt task at a time."
I suggest that anyone working on this follows that advice.

[Alys]

I'm changing this to a medium priority though because it's not as important as some of the bugs we have.

[librarianmage]

Is this still a thing?

[paglias]

done!