I do not know if there is a manual config possible, but the following workaround should help:
Create a folder where you want to install your addons in. Let's say "C:/AddOns" and select that folder in Minion.
Now Minion should be able to install addons inside "C:/AddOns", because that path does not have any special characters.
Then go to "Documents/Elder Scrolls Online/live" and delete the AddOns folder, if it exists in there.
At the top of the current window, click on the address bar and type
cmd and press enter.
A black terminal will open. It should list the current path, i.e. ...Documents\Elder Scrolls Online\live.
Type
mklink /J "AddOns" "C:/AddOns"
and press enter.
This will create an "AddOns" folder in the current location, which is actually just a link to the previously created "C:/AddOns" folder.
Because of this link, when ESO tries to access "Documents/Elder Scrolls Online/live/AddOns" it will actually load all addons from "C:/AddOns".