Install Windows SDK >= 18362 when using VS2019 to fix compilation of UE-4.27.0

[slonopotamus]

resolves #192

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This is an alternative to #193. See discussion in #192.

P.S. Testing is not finished yet.

[TBBle]

At some point, users may want the SDK version to be configurable. But not worth doing yet.

I like this approach, the only risk I see is if a project is using VS2019-incompatible code in their own source in a UE 4.27 project. That'd require a pretty complicated setup to work locally, and unless we find a real person doing this, it's not worth trying to complicate things here.

[TBBle]

Should we also implement MaxSupportedUnreal to go with MinSupportedUnreal?

Or is that too restrictive given both 4.27.1, and the possibility to locally patch 4.27.0 to work with the old SDK and hence support the VS2017 pre-reqs.

I've just realised that (from brief code-inspection) we don't block UE5 with VS2017 either.

[slonopotamus]

Should we also implement MaxSupportedUnreal to go with MinSupportedUnreal?

We should at one point, but not yet. UE5EA can only currently be built as a "custom version", so we effectively treat its version string as an opaque identifier and cannot do conditions with it.

[slonopotamus]

I've successfully build 4.27.0 and 5.0EA2 using these changes, seems good enough to merge. Note that I used --exclude ddc to avoid hitting #196. That thing will be fixed in a separate PR.