Game mode should read from game configuration and be locked on single deployee.

[bingluen]

Description

Relate to #3
Load game mode from game configuration instead of project.json. And only show the page which match the value of game mode. Others page which is not matched should be hidden(return 404 or others).

Task

• Remove defaultMode from project.json
• Add mode (or others key name which can represent "enabled some game mode page and other page will be hidden") into game configuration
  • vuex store on src/store/config
  • implement generator (CCIP-App/CCIP-Puzzle-Config-Generator-Chocolate)
  • document on readme.md