Credentials encoding differences between Environments

[FraWolf]

As title says, I have implemented a different method to calculate and encode credentials for OAuth2 flow. On node.js environment will be used Buffer, and, in the browser-client, will be used btoa() built-in method.

---

This pull request includes several changes to the codebase, primarily focusing on updating contributor information, adding a new utility function, and modifying the OAuth class to check the running environment. Below are the most important changes:

Contributor Information Update:

• package.json: Updated the email addresses and URLs for contributors Francesco Lombardo and Luca Pattocchio.

Utility Function Addition:

• src/adapters/utils.ts: Added a new function checkRunningEnvironment to determine if the code is running in a Node.js environment or a browser environment.

OAuth Class Enhancements:

• src/contents/oauth/index.ts: Imported the new checkRunningEnvironment function and added a private environment getter in the OAuth class to utilize this function.
• src/contents/oauth/index.ts: Modified the btoa method in the OAuth class to use Buffer for base64 encoding in a Node.js environment and btoa in a browser environment.

[Kasui92]

@FraWolf
I've tested the changes in this playground and, aside from the usual Next.js magic of making things happen when they shouldn't, it actually solves the buffer problem.