Auth module improvement

src/app/app.reducer.ts

src/app/core/auth/auth.actions.ts

src/app/core/auth/auth.effects.ts

src/app/core/auth/auth.interceptor.ts

src/app/core/auth/auth.reducers.ts

src/app/core/auth/auth.service.ts

src/app/core/auth/authenticated.guard.ts

src/app/core/auth/selectors.ts

src/app/shared/auth-nav-menu/auth-nav-menu.component.html

src/app/shared/auth-nav-menu/auth-nav-menu.component.scss

src/app/shared/auth-nav-menu/auth-nav-menu.component.ts

src/app/shared/log-in/log-in.component.html

src/app/shared/log-in/log-in.component.ts

src/app/shared/log-out/log-out.component.html

src/app/shared/log-out/log-out.component.ts