Added new methods to identify terminal nets connections plus excitations refactoring

[maxcapodi78]

in particular method
are_port_reference_terminals_connected is doing the following:

• get all ports
• get references object
• get reference net
• for each reference object is getting connected objects
• checks for intersections of those list to see if there is a common return path between ports.

Excitations refactoring includes the following:

• multiple classes for Excitations, Probes and Sources
• A lot of new properties in excitations
• properties are part of Edb class now and shared with core_siwave and core_hfss classes

[codecov]

Codecov Report

Merging #1984 (cefd92b) into main (525b843) will increase coverage by 0.02%.
The diff coverage is 79.50%.

@@            Coverage Diff             @@
##             main    #1984      +/-   ##
==========================================
+ Coverage   80.20%   80.23%   +0.02%     
==========================================
  Files         108      108              
  Lines       46252    46686     +434     
==========================================
+ Hits        37098    37457     +359     
- Misses       9154     9229      +75     

[MaxJPRey]

LGTM.