Add Meta and Security Schemes to tool definition

[zacksmash]

A new property for $meta was added to Tool definitions, which will allow you to attach the _meta output property. Currently, this has only been applied to the Tool output, but may easily be added to other Primitives. This behaves in the same way that $name, $title or $description would.

A new method for securitySchemes() has also been added to tools, which works in a similar fashion to the JSON schema() method. A new static builder class has also been added to assist with security schemes, and type-hinted on the tool method.

Example:

#[IsReadOnly()]
class WeatherTool extends Tool
{
    protected array $meta = [
        'someKey' => 'someValue',
        'foo' => 'bar'
    ];

    //  ...
    
    // Or via the meta() method
    
    public function meta(): array
    {
        return [
            'someKey' => 'someValue',
            'foo' => 'bar'
        ]
    }

    public function securitySchemes(SecurityScheme $scheme): array
    {
        return [
            $scheme->oauth2('mcp:use')
        ];
    }

Ref #99

[zacksmash]

On this one, happy to remove the SecurityScheme class and just define them manually.