Change id of core content pack from 'dda' to 'bn'

[olanti-p]

Summary

SUMMARY: Infrastructure "Changed id of core content pack from 'dda' to 'bn'"

Purpose of change

At the moment, DDA and BN share the same core content pack id - dda. Because of that, any external DDA-compatible mod installed on BN will show up as compatible with BN in UI, but will throw arcane errors when attempting to load the world.

Describe the solution

Migrate to new content pack id:

• Create a new core content pack mod that's just a copy of existing dda mod, but with id bn
• Make dda into an empty obsolete mod that depends on bn
• Change all mainline mods to depend on new bn
• Adjust C++ code to use new id for core content pack

This way:

• All mainline mods show up as depending on Bright Nights
• All external mods that haven't migrated will show up as depending on Bright Nights (wrapper), but will keep functioning
• All existing saves will have the new bn mod automagically loaded because dda now depends on it
• Once the next stable rolls out and external mods have migrated to depend on bn, we can remove dda mod which will make all mods that depend on dda (DDA mods) incompatible with BN.

Describe alternatives you've considered

Hack it by adding "is_compatible_with_bn": true to MODINFO object.

Testing

• Created new world with no mods
• Created new world with mainline mods
• Created new world with mainline mods before migrating them to new id, Bright Nights (wrapper) gets automatically added to mod list
• Loaded an existing save that has only dda in its mod list, Bright Nights gets automatically loaded before Bright Nights (wrapper), but save's mod list stays unchanged (expected behavior)
• Removed dda mod, added dda->bn migration to data/mods/replacements.json and tried to create new (or load existing) world. Result: mods that depend on bn work as expected, mods that depend on dda show missing dependency, saves that use dda have their mod list updated to use bn

[Coolthulhu]

Make dda into an empty obsolete mod that depends on bn

That's surprisingly elegant. For some reason I didn't think of it.