Duplicate .d.ts files into cjs

[jacogr]

Generates output such as -

...
    "./config/typedoc": "./config/typedoc.cjs",
    "./detectOther": {
      "module": {
        "types": "./detectOther.d.ts",
        "default": "./detectOther.js"
      },
      "require": {
        "types": "./cjs/detectOther.d.ts",
        "default": "./cjs/detectOther.js"
      },
      "default": {
        "types": "./detectOther.d.ts",
        "default": "./detectOther.js"
      }
    },
    "./package.json": {
      "require": "./cjs/package.json",
      "default": "./package.json"
    },
...

May address polkadot-js/api#5711 (or at worst not make it worse)

[rflechtner]

From my experiments with patching up polkadot dependencies in the node_modules, I am confident that this would indeed address the issue.
May I ask if we could move this along? Node16 / NodeNext is currently the recommended module setting for most use cases and applications, even when emitting CommonJS module code (https://www.typescriptlang.org/docs/handbook/modules/guides/choosing-compiler-options.html), a combination which is still not useable if any of the polkadot-js dependencies are being used.