CLI does not support tsconfig with comments

[yanniz0r]

Describe the bug
By default, initializing a project with tsc --init creates a tsconfig file with a lot of comments inside. I usually leave them in. If you run the cli method yarn mikro-orm cache:generate runs into an error when comments are present.

Stack trace

(node:8435) UnhandledPromiseRejectionWarning: SyntaxError: /Users/*****/Project/Private//*****/tsconfig.json: Unexpected token/ in JSON at position 259
    at parse (<anonymous>)
    at Object.Module._extensions..json (internal/modules/cjs/loader.js:1234:22)
    at Module.load (internal/modules/cjs/loader.js:1049:32)
    at Function.Module._load (internal/modules/cjs/loader.js:937:14)
    at Module.require (internal/modules/cjs/loader.js:1089:19)
    at require (internal/modules/cjs/helpers.js:73:18)
    at Function.registerTsNode (/Users//*****/Project/Private//*****d/node_modules/@mikro-orm/core/utils/ConfigurationLoader.js:57:30)
    at Function.configure (/Users//*****/Project/Private/*****/node_modules/@mikro-orm/cli/CLIHelper.js:38:13)
    at /Users//*****/Project/Private//*****/node_modules/@mikro-orm/cli/cli.js:16:1

To Reproduce
Steps to reproduce the behavior:

1. Create a new project and initialize it with tsc --init
2. Add mikro orm cli and bootstrap the app with database connection etc.
3. run yarn mikro-orm cache:generate

Expected behavior
Either should the error be more clear, something like The provided tsconfig is invalid. Please keep in mind that comments are not allowed or it should support comments.

Additional context
A tsconfig that allows reproduction of the issue looks like this:

{
  "compilerOptions": {
    "target": "ES2017",
    "module": "commonjs",
    "outDir": "./dist",
    "strict": true,
    "baseUrl": "./src",
    "esModuleInterop": true,
    "experimentalDecorators": true,
    "forceConsistentCasingInFileNames": true
  }
}
/** Test */

Versions

Dependency	Version
node	14.4.0
typescript	3.9.6
mikro-orm	4.0.0-rc.0
your-driver	pg