Duplicate entries in the doxygen documentation

[vkresch]

Currently there is a bug in the doxygen documentation in which enum types have duplicate display. See screenshot below from here:

[vkresch]

Solution:
Exclude osi3 folder from doxygen generation since doxygen searches recursively for comments in open-simulation-interface folder and osi3 folder which was generated through the python setup build hence parsing twice the same comments.
Here are some test runs.

Commit change:
586c3ab

Pull request:
#340

[vkresch]

Just to have an updated documentation I also suggest we use a newer dist to run the CI and add a treeview to the documentation for easier browsing through the fields. (See here example docu from my repo)

[jdsika]

Thank you @vkresch for the quick and efficient fix.