Configure Tender app to use login Firebase & LoginForm

[omiras]

Create a new view: view/Login.vue Inside the Login view, we'll show LoginForm.vue or SignInForm.vue or RecoverPassword.vue

The aim of this issue is to configure the Tender app to use firebase to log in and create the LoginForm

1. Configure Tender (main.js) to use the firebase backend to authenticate
2. Create the LoginComponent.vue component
   1. Try to design it as close as possible to the wireframe and syling criteria (maybe help from Alba or Silvia will be needed)
   2. The LoginComponent should be able to perform the most typical user stories with authentication

Register new user - LoginForm.vue

1. An user should be able to register himself with username/password
2. Password should have a minimum strength (check for some info about safe password and validations).
3. Please take into consideration what happens if a username is already registered (email address). Most likely we have to display a mesage to the user
4. Once we Sign Up; we'll show a new view (NextSteps?) ; where the user should choose if he/she wants to adopt or give an adoption.

Sign in

1. A registered user should be able to sign in with his credentials
2. If the user signs in successfully; we'll redirect the user to the Profile page
3. Create a ProfileComponent.vue for the Profile page. At this moment, this component will only display the user's email.
4. If the credentials are wrong, an error message should be displayed

To check that login is working properly, simply show a console.log to display which is the email of the logged user.

[omiras]

1. When the user logs in; update the 'loggedUser' state property with this info.
2. Create a mutation which is commited by the actoin 'signin', to alter the 'loggedUSer' property with the 'user' property that firebase provides

[omiras]

1. Use the same workflow for the sign up feature
2. Once signup is successful, user should be sign in automatically.