Users should receive activation email from us before their account is operational

[mojtaba-eshghie]

• Should schedule sending an email when the user first registers, I need to modify email-service
• Should first modify the User.js model on the server-side to include the activation state.
• Create a new middleware in auth.js to check the user activation status; this middleware will be used on virtually any permissioned controller
• Modify the Login.js so that it reflects the user being or not being activated.