Hide lauchers when not "separate launchers"

After !1744 (merged) launchers are always present in the traditional task manager no matter what. also, the separateLaunchers option doesn't make much sense putting launcher icons besides their running task.

In a discussion in that merge requests was agreed that this option should intead hide launchers in TTM to keep a behavior similar to the previous, but was merged without it, so this implements that.

Not being possible to hide launchers anymore is kinda a problem for ttm as its main feature is to keep window titles as readable as possible, and if one has a large amount of launchers, they go to bite in the space for the labels.

I do get the reasoning for having this behavior as default as it gives always an immediate feedback to the "add launcher" actions, but it just doesn't work for me.