replace baby_egg, baby_monster, baby_monster_group with struct

[GuardianDll]

Summary

None

Purpose of change

having three (now four) different field that need to be compared against each other all the time? let's just move it to something better

Describe the solution

Shove baby_egg, baby_monster, baby_monster_group to struct
Add new type, baby_egg_group
Compare each one against each other to prevent user using more than one by accident
replace all json syntax with regex (something like "baby_egg": "(.*?)" and "baby_type": { "baby_egg": "$1" })
replace all using in code using the struct

• document
• finish unit test moved to Make reproduction CI test #76294

Testing

1 spawn eggs

2 spawn books from itemgroup

3 spawn dogs

4 spawns cats from cat group

[Maleclypse]

No gods no kings no tests! Do you want me to wait until the test PR is also passing?

[GuardianDll]

Nope, test relies on yet another PR by Ren, that's partially the reason i moved it to separate pr