refactor: split mergedTemplate into debounce.ts and objectUtils.ts

[moe-moe-pupil]

Summary

• split mergedTemplate into debounce.ts and objectUtils.ts from DeveloperMode.ts

Why

• these functions have nothing to do with DeveloperMode.ts, these are utils functions.
• DeveloperMode.ts is too large, it has 731 lines now, for some best practice, one file should not larger than 400 lines

How to test

• I tested it, it works as before editMapTile.txt