Ft leave out ctrldev from zs3 loading

[pft]

Fixes zynthian/zynthian-issue-tracking#1534

This goes to the heart of the Zynthian, and I do not presume to understand everything fully, so please review carefully.

[jofemodo]

Hi @pft !
Please, could you explain what are you trying to achieve here?
Also, please, don't send more "changes" to oram branch. Only bugfixes.
All changes, improvements, new features must be done in vangelis now.

[pft]

Hi @jofemodo!

Let's say I've made some nice setup with zs3's while having a certain ctrldev driver loaded, say apc key 25 mk2.

Now, when I change to use APC Key 25 + SL (for using SooperLooper), and I recall a zs3, the driver that I had in use while creating those zs3s suddenly gets loaded instead.

This PR leaves out the loading of drivers that were running at the time of zs3 creation, except for when loading last state.
It also adds the option to just load those drivers, for the off chance it makes sense. Could be in a variety of settings: quickly load the ctrldev drivers for the stuff you have available at home vs. the stuff in the studio.

Personally I think ctrldev preferences have little to do in a zs3 (except for being a convenient place for the Last State Functionality). But I love to be proven wrong ;). Maybe ctrldev preferences should go somewhere else entirely.

Upcoming PRs will be to vangelis yes. I made this PR before the big zynbleton makeover I think.