Add components with variable port count

[cpfannenmueller]

The components that are able to have a variable amount of Ports (e.g. mux, demux, ic, rotary switches,…) are currently not included. Therefore a way to define the port amount would be necessary without recompiling the TeX in "Symbol Convert"-Import Tool

[JPWiedemann]

We probably have to rework the component system in the UI. Essentially, the plan is to support the standard node and path components similar to the current system but make the system expandable to also include custom components. Their custom symbol behaviour would then have to be recoded in js for these symbols. This will be a lot of work even before adding these custom symbols so don't expect this in the near future