feature: add multiple disks

[azadevlab]

using MR style like - #494

Summary
This MR changes storage-path settings from single string value entry to a dynamic list of paths
PLEASE PAY ATTENTION THAT schemas/gschemas.compiled RE-COMPILED
much better if any maintainer will re-compile and push from his side. After xz history (with test bin files) we can't trust to binaries from non old maintainers

Old situation
Just single path can be added

New situation
Multiple paths can be added

Changes Made

• "storage-path" changed from str to list, due changed in schema had to rebuilt schema glib-compile-schemas)
• [crutch solution, but less painful] -
• 1. added new method _setup_storage_list for re-defining Gtk.Entry UI interface from single value window to dynamic container Gtk.Box ;
• 2. entry.connect('activate') + let focusController - otherwise if we type for example /home, it will shows in sensors like /h , /ho, /hom and finally /home, by this dirty hack we adding sensor only after "Enter" or after closing the window, so we will get just /home
• parallel reading stats and using for each sotrage-path

Testing

• No startup errors
• No errors during adding/removing items or when changing settings

Screenshots/Visual Changes

[azadevlab]

please could you merge this MR due would be very helpful, using btrfs and it help me watch of usage "/home" and "/"
thanks in advance, also this MR will close these tickets/issues
#503
#143
#455

[yannikthegenius]

+1