Implement OS checks

[terrajobst]

We decided in #40111 (comment) to expose OS checks as static helpers on OperatingSystem. We need to implement those:

namespace System
{
    public partial class OperatingSystem
    {
        // Primary
        public static bool IsOSPlatform(string platform);
        public static bool IsOSPlatformVersionAtLeast(string platform, int major, int minor = 0, int build = 0, int revision = 0);

        // Accelerators for platforms where versions don't make sense
        public static bool IsBrowser();
        public static bool IsLinux();

        // Accelerators with version checks

        public static bool IsFreeBSD();
        public static bool IsFreeBSDVersionAtLeast(int major, int minor = 0, int build = 0, int revision = 0);

        public static bool IsAndroid();
        public static bool IsAndroidVersionAtLeast(int major, int minor = 0, int build = 0, int revision = 0);

        public static bool IsIOS();
        public static bool IsIOSVersionAtLeast(int major, int minor = 0, int build = 0, int revision = 0);

        public static bool IsMacOS();
        public static bool IsMacOSVersionAtLeast(int major, int minor = 0, int build = 0, int revision = 0);

        public static bool IsTvOS();
        public static bool IsTvOSVersionAtLeast(int major, int minor = 0, int build = 0, int revision = 0);

        public static bool IsWatchOS();
        public static bool IsWatchOSVersionAtLeast(int major, int minor = 0, int build = 0, int revision = 0);

        public static bool IsWindows();
        public static bool IsWindowsVersionAtLeast(int major, int minor = 0, int build = 0, int revision = 0);
    }
}

/cc @jeffhandley @buyaa-n

[akoeplinger]

Do we want to implement them using the same underlying RuntimeInformation architecture?
So running RuntimeInformation.IsOSPlatform(OSPlatform.Create("iOS")) would return true because it just forwards to OperatingSystem.IsOSPlatform()?

[terrajobst]

I consider that an implementation detail. In my head, the impl looked something like this:

        public static bool IsOSPlatform(string platform)
            => RuntimeInformation.IsOSPlatform(new OSPlatform(platform));
        public static bool IsOSPlatformVersionAtLeast(string platform, int major, int minor = 0, int build = 0, int revision = 0)
            => IsOSPlatform(platform) && Environment.OSVersion.Version >= new Version(major, minor, build, revision);

        public static bool IsFreeBSD()
            => ISPlatform("FreeBSD");
        public static bool IsFreeBSDVersionAtLeast(int major, int minor = 0, int build = 0, int revision = 0);
            => ISPlatform("FreeBSD", major, minor, build, revision);

        ...

[akoeplinger]

Ok yeah I agree it is an implementation detail but ideally the two APIs should align like in your example.

It'd be bad if in the future when we add a new platform we'd need to add it in two places or worse if RuntimeInformation.IsOSPlatform(OSPlatform.Create("AppleWashingMachine") returned a different value than OperatingSystem.IsOSPlatform("AppleWashingMachine")