Implement New Functions for s3 service

[beinfluential88]

Implement Playlist service features:

• A function to get the playlist based on its id
• A function to create the playlist
• A function to delete the playlist
• A function to add songs to the current playlist
• A function to delete a song from the current playlist
• A function to edit the name of the playlist
• A function to edit the order of the songs in the playlist (Nice to have)

TASKS:

• add edit_playlist_name function
• add delete_song function
• add add_song function
• add delete_playlist function
• add create_playlist function
• add get_playlist function
• add list_all_playlists

[bingsoorim]

• Update app.py
• Update Readme