[7.x] Support tls:// scheme when using url in Redis config

[tillkruss]

Currently, the protocol can't be specified when using the Redis url configuration. The config below would connect via TCP without any warning.

return [

    'redis' => [

        'client' => env('REDIS_CLIENT', 'phpredis'),

        'default' => [
            'url' => 'tls://127.0.0.1:6379?database=0',
        ],
    ],

];

This PR adds support to specify protocols:

return [
    'default' => [
        'url' => 'redis://127.0.0.1:6379?database=0', // scheme is ignored, connect via TCP
    ],

    'cache' => [
        'url' => 'tcp://127.0.0.1:6379?database=1', // connect via TCP
    ],

    'sessions' => [
        'url' => 'tls://127.0.0.1:6379?database=2', // connect via TLS
    ],
];