fix!: sync .well-known dir by default

[sesi200]

Description

Well-founded complaint:

May I ask what's the reasoning between not allowing .well-known folder per default and forcing each developers to whitelist this folder in ic-assets.json?
I had to answer and explain countless time, often per private message, how to set up such a file. It's becoming annoying, particularly when I'm pinged late in the evening, therefore I am curious to know if there is a valid reason.

This PR automatically adds .well-known to the list of synced directories

Fixes SDK-1408

Inspired quite a bit by #2948

How Has This Been Tested?

Added unit tests

Checklist:

• The title of this PR complies with Conventional Commits.
• I have edited the CHANGELOG accordingly.
• I have made corresponding changes to the documentation.