Describe the bug
I hope the title is clear and concise enough.

To Reproduce
Steps to reproduce the behavior:

1. View latest code https://github.com/Facepunch/Facepunch.Steamworks/blob/master/Facepunch.Steamworks/Structs/UgcQuery.cs#L15
2. Search "creatorApp" or "consumerApp"
3. Observe there are no ways for the caller to explicitly set these, while consumerApp will implicitly use SteamClient.AppId when it is zero and then creatorApp will be set to consumerApp when zero too.

Calling Code
https://github.com/Facepunch/Facepunch.Steamworks/blob/master/Facepunch.Steamworks/Structs/UgcQuery.cs#L15

Expected behavior
When you're using this wrapper to implement a Workshop tool that publishes for a different app (the game), one needs to be able to set these individually. The Workshop tool is the creatorApp, and the game is the consumerApp. So without APIs to set these existing fields, this throws a wrench in things.

Desktop (please complete the following information):

• OS: Windows, but this isn't platform specific
• Unity: Not using Unity

Additional context
If no one else takes the time to address this, I'll probably set aside time in December to throw up a PR for adding some APIs which are needed here (WithConsumerAppId, etc as it appears that is the pattern used elsewhere).