Add login

[ManOfTheMask]

Add a way to login it's basically gonna be the same as signing up instead it's just gonna login

[ManOfTheMask]

User enters private key and passphrase then the frontend sends a request to the backend to see if the user is in the database via getting the public key and sending it to the server for verification. If the public key is matched in the database the server will send an encrypted message in response that must be decrypted by the private key. If decrypted then the decrypted private key gets stored in session until the user logs out or the browser tab closes then the user will have a session cookie send by the server that will act as a login cookie and whenever the user needs to decrypt the encrypted messages loaded from the server it can grab the decrypted private key without needing to keep inputting the password and it will be cleared when browser tab closes or user logs out.