Add rule for calculations doesn't work

[lassopicasso]

Description of the bug

When adding a rule for calculations, Altinn studio crashes consistently. The code used here is quite old and needs to be refactored as well.

Edit: see comment below.

https://github.com/Altinn/altinn-studio/assets/74791975/e7f02be7-4ee2-457d-abd7-66d37451fd90

Steps To Reproduce

1. Go to the "Lage" page.
2. Add a component.
3. Click on the "Beregninger" accordion.
4. Click on the plus icon for "Regel for beregninger."
5. Select a rule, and it will crash.

Additional Information

No response

[nkylstad]

I'm wondering if we should deprecate support for this. By that, I mean:

• Remove functionality to add/edit client calculation rules from the GUI
• Add information message saying that this is deprecated
• Add link to documentation on how to work with calculations back-end
• Keep link to Gitea, allowing user to manually edit config files related to this.

I think we should keep the code for a while, with comments about it being deprecated. Then we can see if we get any feedback from users who are missing this functionality. If so, we can bring it back and fix it. If not, then at some point we should consider removing it from our codebase entirely.