Add user module, implement authentication

config/config-dev.json

config/config-rec.json

package-lock.json

package.json

patch.js

src/app/app.module.ts

src/app/app.routing.module.ts

src/app/components/welcome/welcome.component.html

src/app/components/welcome/welcome.component.scss

src/app/components/welcome/welcome.component.ts

src/app/services/app-config.service.ts

src/app/user/components/index.ts

src/app/user/components/login/login.component.html

src/app/user/components/login/login.component.scss

src/app/user/components/login/login.component.spec.ts

src/app/user/components/login/login.component.ts

src/app/user/guards/authenticated.guard.ts

src/app/user/guards/index.ts

src/app/user/guards/unauthenticated.guard.ts

src/app/user/interceptors/auth-interceptor.ts