feature/ts-support: Add new loader

[ShadyMind]

• Move typescript dependency to regular dependency
• Add typescript loader
• Add test for typescript file

[azu]

Thanks for PR!

I think that TypeScript as config file is difficult.

1. rc-config-loader does not provide your config type

• It means that .ts support just compile the config file
• It looks like useful, but I feel it is not complete
• If pass the type check, but it may not filled config schema

2. typescript package does not apply semantic versioning
   • It make difficult typescript as dependencies
3. typescript is large and heavy
   • https://packagephobia.com/result?p=typescript 60MB+
   • TS complation is slow(main reason come from type checking)

Summary: I feel it is an incomplete solution. On the other hand, maintenance costs will go up.
So, It is out of scope in current.

📝 We can resolve 2 and 3 by using peerDependencies, but it will be complex to use.
For example, webpack allow to use webpack.config.ts.

• https://webpack.js.org/configuration/configuration-languages/

However, documentation is something wrong. I think this shows the complexity of TypeScript.

• ts-node docs tweaks webpack/webpack.js.org#6154

📝 I feel that a method like $scheme property of JSON Schema is a realistic solution.

• [feat] Allow $schema field in tauri.conf.json tauri-apps/tauri#3464
• 🚀 Feature: Config file schema mochajs/mocha#3727
• JSON Schema Store

Thanks for investigate!