Export TS types in a separate entry point via 'mediasoup-client/types'

## Details

The idea is that, instead of exporting types like this:

```ts
import { types as mediasoupClientTypes } from 'mediasoup-client';
```

We import them this way:

```ts
import types as mediasoupClientTypes from 'mediasoup-client/types';
```

## TODO 1

I've briefly tested this and it looks like for this to work, the parent application must have in its `tsconfig.json`:

```
"module": "nodenext",
"moduleResolution": "nodenext",
```

Is this ok? Any other implications?

## TODO 2

Should we stop exporting `types` from 'mediasoup-client' and instead force applications to import them from 'mediasoup-client/types'?

## TODO 3

We should export `HandlerInterface` type so applications do not need to do this ugly thing:

```ts
import { HandlerFactory as MediasoupClientHandlerFactory } from 'mediasoup-client/lib/handlers/HandlerInterface';
```

package.json

@@ -16,11 +16,21 @@
 		"type": "opencollective",
 		"url": "https://opencollective.com/mediasoup"
 	},
-	"main": "lib/index.js",
-	"types": "lib/index.d.ts",
+	"main": "./lib/index.js",
+	"types": "./lib/index.d.ts",
+	"exports": {
+	  ".": {
+	    "import": "./lib/index.js",
+	    "types": "./lib/index.d.ts"
+	  },
+	  "./types": {
+	  	"import": "./lib/types.js",
+	    "types": "./lib/types.d.ts"
+	  }
+	},
 	"files": [
-		"npm-scripts.mjs",
-		"lib"
+		"./npm-scripts.mjs",
+		"./lib"
 	],
 	"engines": {
 		"node": ">=18"