GameJolt appears to support RMMV games seeing as there's already a few of them on there. You're free to distribute your game however you please, provided you comply to these conditions:
- You have a legitimate copy of RMMV, which in turn gives you license to distribute your project
- Any custom resources like graphics, music or plugins included comply with the author's terms of use.
- You acknowledge putting your game out to the market exposes it to scrutiny by a lot of people, and that there is a chance people don't like it. Hell, they may hate it so much they threaten your life and harass you til you're forced to flee anroad and change your name forever.
The last bit is a joke. Sort of.