Add blade directive to know if account is linked

• add blade directive hasDiscordLinked and hasNotDiscordLinked

Examples

     @plugin('discord-auth') {{-- if plugin discord-auth is enabled --}}
           @guest  {{-- if user is not authenticated --}}
                 <a href="{{ route('discord-auth.login') }}">Connect with discord</a>
          @endguest
    @endplugin

     @plugin('discord-auth') {{-- if plugin discord-auth is enabled --}}
           @auth  {{-- if user is authenticated --}}
                @hasNotDiscordLinked {{-- if user hasn't a discord account linked --}}
                     <a href="{{ route('discord-auth.login') }}">Link your account with Discord</a>
                @endhasNotDiscordLinked
           @endauth
    @endplugin

Account association

• Ability for a user to associate his discord account to his existing account. Users just need to access the /discord-auth route when they are logged in.
• If a user is not logged, try to login via discord, and the email address of the discord account already exists in Azuriom database, he will be asked to log in to this account using the concerned email and password to associate his discord account.

1.0.0

add config via config panel