Moved bluebell flower to obsolete

[snipercup]

Summary

SUMMARY: Content "Move bluebell_flower to obsolete"

Purpose of change

Was sitting in /items/generic.json and nothing except for 2 tilesets were referring to it.

Describe the solution

Moved to obsolete

Describe alternatives you've considered

Finding a use for it, but #14961 states that bluebell flowers are useless and they were removed from spawn.

Additional context

Found it using my json analyser

The game still allows you to spawn it using debug

[jbytheway]

It sounds like you have a json analyser that can detect items which are not referenced (and perhaps other issues). I was thinking that we should have such a check in the CI tests. Are you planning to add it once the errors it finds are resolved?

[snipercup]

I lack the skill to add it. I can do Javascript but not C++ (yet). It's a resource heavy algorithm so if it were to be added, it should be written efficiently. I already fixed the most obvious items that were not referenced. I think it's good to run it from time to time. Balancing item weight is a bigger challenge though.

[AMurkin]

Github action could be implemented on node.js.
See https://github.com/CleverRaven/pr-validator and https://help.github.com/en/actions/automating-your-workflow-with-github-actions.

[snipercup]

Thanks for the suggestion. I may visit it at a later time. I'm working on other stuff atm. I recall it took 10 minutes to analyse the existence of every vanilla item (mods not counted). In the meantime anyone can look at my repo and find the item existence analyser and its code.