Add the ability to create an account session

[Christian-Toney]

The server should return a 400 if the login ID and password are incorrect. The server should also return a 400 error if the login ID doesn't exist. These errors should not be distinguishable, as this encourages malicious actors to guess account information.

Completion criteria for developers

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1. Add endpoint: POST /accounts/user/sessions
2. Return a 400 if the account login ID doesn't exist
3. Return a 400 if the account login ID and password are incorrect
4. Return a 403 if the user account is disabled
5. Encrypt a random token and store it onto the database, along with the creation date and the IP address that requested its creation
6. Return the unencrypted token to the client