Enhanced methods.allActive() for integration consistency and added methods.list()

[sandervanhooft]

This PR ensures integration consistency: methods.allActive() now returns the full set of activated methods regardless the currencies supported.

Context: Mollie added support for twint recently, which does not appear on /v2/methods by default because Twint does not support the EUR currency.

To mirror the API, the list() method is added for directly interacting with v2/methods.

$mollie->methods->list(); // Directly interact with the "/v2/methods" endpoint
$mollie->methods->allActive(); // Enhanced for consistency: returns all methods regardless the currencies supported