Add a SupportedOS attribute to the BuildParameter class

[Aeinot]

Hi,

For agents supporting multiple OS, it would be useful to be able to associate a BuildParameter with a single OS.

The configuration UI for a new payload could then display only the parameters relevant to the OS chosen for the build.

Thanks for all your great work on Mythic!

[its-a-feature]

That needs to get added in addition to a conditional parameter group similar to how the conditional parameter groups work for tasking