Sky Archipelago

- [Added]: Stronghold Support. (Island creation + protection range in which a stronghold will spawn).
- [Added]: Deepslate spawning with configurable Y-level for when deepslate should spawn. (Available in advanced menu).
- [Added]: Players will spawn only on an anchor island upon world creation. 
- [Added]: Export configuration to clipboard to paste into dediated server config. (No more manual 1 by 1 entering).
- [Added]: Toggle to disable rule structure spawning mechanism. (Use at your own risk, this will just let ANYTHING spawn ANYWHERE).
- [Added]: Cluster spacing mode `CONSISTENT` & `DYNAMIC` to allow for variable cluster distances and set distance. 
- [Added]: Built-in presets (Survival-ready preset available for use).
- [Added]: Preset to be assigned as default settings. (No need to keep loading a preset you love, just set it as default and every world after will use that as long as world is set to sky island).
- [Added] Default preset assigned persistance, if you close Minecraft and open it again, it will retain the default assigned by you. 
- [Added]: Enable/Disable Satellite islands from spawning (Part of clusters around anchor islands).
- [Added]: Enable/Disable Spire islands from spawning (Part of clusters around anchor islands).

- [Changed]: Reset defaults button now will reset to your assigned default preset (if none, defaults to hardcoded values).
- [Changed]: Max Island radius is now 500.
- [Changed]: Configuration description/naming to be clearer. 
- [Changed]: Advanced Config screen to be more in line with existing configuration flows. 

- [Fixed]: Players will no longer spawn in the void when using low density and high cluster spacing. (New custom fallback mechanism will scan further to find the first available anchor island).