Refactoring: transform serializer to visitor, suppress state, isolate logic

[loulecrivain]

WIP

[loulecrivain]

all tests passing! I have refactored only the switch serializer for now. there is a lot of additions since the new code is a bit more verbose and I had to add tons of classes to be able to have that "framework".

[johannwagner]

Very neat implementation, I like it a lot!

I would like to talk in a call about the code paths around CPE filter list generation and bgp:cpe in general to get a better understanding!

Otherwise, it is mostly clean-up and nitpicking, but a call to go through this together and do some knowledge transfer would be a good idea anyways.

[loulecrivain]

OK, I'll work on fixing the differences in config generation in ansible_junos and rtbrick-prod. I'll ping you when it's done 😉

[loulecrivain]

@johannwagner all differences on ansible_junos are resolved, ready for review!

[loulecrivain]

FYI I changed some stuff in the L2VPN visitors.

Now all L2VPN types and their available encapsulations are modeled with dedicated types.

The code is a bit more boilerplate, but in the end it's less lines than before (!) and IMO less error-prone, since we no longer have to meddle in with all the different cases for L2VPN types.

The only thing to pay attention to is the order of the encapsulation traits, the one with the most priority should always be 1st.

If you have some ideas to make this part simpler, feel free. Didn't really find a satisfactory solution on my end.

[loulecrivain]

🥳