Make the trySignInSilently method as the default sign in method

[thivi]

The current signIn method leads to poor UX since it involves browser redirections. In contrast, the trysSignInSilently method allows signing in without redirections.

However, this method requires the user to have already logged into the server. This can be improved by modifying the method to trigger an OIDC flow if the user is not signed into the server. And this method can be renamed as signIn while renaming the signIn method to something like signInWithRedirection.

Points to consider: #42 (comment)