Replaces dots to slashes of DSN adapter.

Currently the adapter only works if class file stay inside of "PluginName/Model/Datasource". This works fine with Mongodb datasource plugin:

    AD7six\Dsn\Wrapper\CakePHP\DbDsn::parse('mongo+Mongodb.MongodbSource://...');

But some CakePHP datasources plugin can have a different path to class file:

    "MyPlugin/Model/Datasource/Database/MyCustomDbo"

And this don't works:

    AD7six\Dsn\Wrapper\CakePHP\DbDsn::parse('schema+MyPlugin.Database/MyCustomDbo://...');

With this change is possible define the path of datasource class file.

Example:

    AD7six\Dsn\Wrapper\CakePHP\DbDsn::parse('schema+MyPlugin.Database.MyCustomDbo://...');
    [
        ...
        'datasource' => 'MyPlugin.Database/MyCustomDbo'
        'adapter' => 'MyPlugin.Database.MyCustomDbo'
        ...
    ]

Sincerely I don't know if this is a best approach to fix it.