Add premium endpoint and token authentication support for Geonames provider

[AronNovak]

Summary

This PR adds support for Geonames premium accounts by introducing optional token and secure parameters to the Geonames provider.

Changes

• Added optional $token parameter to the Geonames constructor for premium account authentication
• Added $secure boolean flag to enable the secure HTTPS endpoint (https://secure.geonames.net)
• Implemented dynamic base URL selection based on the $secure flag
• Added appendToken() method to append the token parameter to API requests when provided
• Updated all API endpoint calls to use the dynamic base URL and token parameter

Benefits

• Enables use of Geonames premium accounts with token authentication
• Supports the secure HTTPS endpoint for premium users
• Maintains full backward compatibility with existing free accounts using username-only authentication
• No breaking changes to existing code

Testing

• Tested with premium Geonames account using token authentication and secure endpoint
• Verified backward compatibility with username-only authentication

Documentation

Premium accounts can now be used as follows:

$provider = new Geonames($client, 'username', 'token', true);

• username: Your Geonames username
• token: Your premium account token (optional, defaults to null)
• secure: Use secure endpoint (optional, defaults to false)

[jbelien]

Thanks a lot for your PR.

On top of the following comments, here are a few extra remarks:

• Is secure.geonames.org only available if you provide a token?
  Your PR description seems to say so but the code doesn't reflect that.
• Please add some tests for the use of $token and $secure.
  You'll have to update phpunit.xml.dist and temporarily set your token (do not commit it), the response using your token will be cached in .cached_responses so we can keep testing it without needing your token.

Thanks.

[AronNovak]

@jbelien Thanks for the feedback, I addressed the points of the review.

[jbelien]

Thanks. Your new tests do not seem to pass ; could you have a look ?