Add method to get artist by id

[Leogendra]

Description

This PR adds a new method to fetch artist details using their Spotify ID, Fixes #13 .

Changes

• Added get_artist_by_id(self, artist_id: str) -> Mapping[str, Any]
  • Uses queryArtistOverview to retrieve full artist details.

Example Usage

artist = Artist()
data = artist.get_artist_by_id("53XhwfbYqKCa1cC15pYq2q")
print(data)  # Returns full artist details

[Aran404]

There's a few things that are wrong here. I'll fix it when I have some more time.