refactor SGObject hacks

[vigsterkr]

SGObject::dispatch_array_type SGObject::get_dispatch_all_base_types and related methods are all hacks that should be implemented using visitor patterns.

[ktiefe]

First draft
#4775

please check if it is a right way to resolve it.

[ktiefe]

probably i will need to use this:
https://www.etlcpp.com/blog/2017/11/12/templated-implementation-of-the-visitor-pattern/

for next step.

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.

[stale]

This issue is now being closed due to a lack of activity. Feel free to reopen it.