fix: sql query updateLoginInformationByUsername used in-database hashing;
refactor: renamed LogOutAccounts into LogOutSessions in models/auth;
refactor: added error checks on opening transactions for all auth service methods;
refactor: added error checks on commiting transactions likewise;
refactor: simplified PasswordResetBegin logic;
feat: implemented PasswordResetComplete method of auth service;
feat: implemented registration emails;
fix: config variables for password length used the same env variable;
refactor: all available config variables added to docker-compose.yml
fix: error handling in auth service for database;
refactor: removed redundant taken email check;
chore: removed todos that were completed/not needed;
fix: leaking transactions in complete registration and login on error;
refactor: got rid of txless requests during transactions;
