Add new placeholders `{site-id}` & `{reward-id}` for reward commands

[NoltoxGit]

Hello,

I would like to suggest a simple improvement regarding the available internal placeholders when running reward commands with the Vote plugin.

Currently, you can use:

• {player} = Returns the username of the user who voted
• {site} = Returns the name of the site linked to the distributed reward
• {reward} = Returns the name of the distributed reward

I propose to add the following placeholders:

• {site-id} = Returns the ID of the site linked to the distributed reward
• {reward-id} = Returns the ID of the distributed reward

This would allow for greater flexibility in custom commands, especially for advanced integrations or specific use cases.

Thank you for your consideration!