refresh token

[fredrikj31]

• feat(database): adds refresh_tokens table to init.sql file
• feat(schemas): adds refresh token schema
• feat(database): adds queries to check and create refresh token
• feat(routes): adds /token endpoint and handler
• feat(database): adds getUserById function
• feat(login): extends login handler with refresh token generation
• feat(helpers): adds validateJwt function
• feat(helpers): adds proper error handling for signJwt function
• feat(http): adds token http call