Make SkyCAD more responsive/fast on large projects

Related sub-tickets:

- Send all tree view query requests to threading so we get a progress bar if it takes a long time to execute. (Fixed.)

- Rendering of sheets becomes super laggy when many objects are selected in tree view (Fixed.)

- Assigning part from catalogue laggy on large projects (Fixed.)

- Inserting symbols and deleting symbols on a sheet slower when large reports are open in the view tab area. (Fixed.)

- Automatic opening of views after opening a project should only show last open view once theye are all open. (Fixed.)

- First element selected (which triggers library association) unnecessarily triggers full reset of cached values. (Fixed.)

- Process which updates connections to be optimased; it makes sheets modification laggy on large sheets with many connections. (Fixed)

- Optimise process to list association blocks (Fixed)

- Optimise Cabling process associated to Cable indicators (Fixed)

- Improve cached connection groups reset so that it only resets pertinent connection groups (instead of all of them as soon as something changes.) (Fixed)

- Undo takes a long time on large sheets with lots of content (Fixed)