Add an option for Retroachievement links [Enhancement]

[xCeeTee]

Describe the solution you'd like
If a game such as Pokemon Red has a Retroachievements page then the link should open that page so you can check your progress/look at any comments for tips.

Describe alternatives you've considered
I've tried setting it up as a custom link, but AFAIK it's impossible on the user-end to utilise the RA API to return the correct ID of the game. Tonnes of romhacks have achievements now so the API would be needed to find the correct game ID going off of the game name rather than RomName, I presume.

[HerrKnarz]

Add Retroachievements