CLI: Add `init` command using Optique

[sij411]

Summary

Add init command to cli with Optique instead of cliffy.

Problem

For now, init.ts has an empty function only. It should be implemented to run as same as original cli with cliffy does, but with Optique. Also it should be cross-runtime so existing Deno API should be replaced to Node API.

Proposed Solution

1. Add init.ts
2. Add init.test.ts

Alternatives Considered

.

Scope / Dependencies

• fedify/packages/cli/src/mod.ts
• fedify/packages/cli/src/init.ts
• fedify/packages/cli/src/init.test.ts

[2chanhaeng]

@dahlia Can I take this issue? #398 will be resolved by merging #401.

[dahlia]

@2chanhaeng Okay!