cppwinrt code base should have clang-format style formatting enforced automatically

[dmachaj]

Closes #1459

Why is this change being made?

Over time a lot of style inconsistencies have snuck into this code base (including things like tabs vs. spaces within a single file). These aren't in and of themselves a big deal but it is nice to apply tooling to this type of problem so that it becomes automatic and we don't have to worry about it during code reviews.

Briefly summarize what changed

This set of changes follows the pattern established by WIL in microsoft/wil#416, with some modifications. The .clang-format file in use here is a copy of the WIL file, with some light modifications to reduce the number of lines churned. Settings like "don't indent the first level of namespace" touched a massive fraction of lines of code so those were relaxed to more closely match the exsting patterns in this repo. I also decided to embed the "check formatting during CI" directly in the YML instead of having a separate script for it. I think that is specialized enough that it belongs in the YML whereas having multiple formatting batch files can be confusing.

The build_test_all.cmd script was modified to automatically run clang-format before building the code. I think most/all contributors rely on that script so that should make formatting automatic and therefore not something that needs to be worried about at all.

The PR build pipeline was also modified to run clang-format before building and will fail if any of the modified files has changes from formatting. This will insta-fail any PR builds that don't match formatting requirements. Therefore any PRs that build successfully meet the style and nobody has to review for style.

By far the biggest set of changes come from the formatting. Just about 100% of files have some sort of change made to them. Many files have tiny/trivial changes. Some had a lot of formatting changes. I tried to tweak the configuration a bit to reduce the churn as much as possible while still becoming consistent across the repo (see https://clang.llvm.org/docs/ClangFormatStyleOptions.html for the full list of options).

We can debate style choices as part of this PR to try and find the ideal balance between desired style and lines churned. I'm happy to tweak the .clang-format file based on feedback.

A very small set of locations had formatting disabled because I wasn't sure if it was doing the right thing. We can add more suppressions if necessary.

How was this change tested?

build_test_all.cmd locally.

[DefaultRyan]

What's happening here? Earlier in this same file, it left these reference parameters left-aligned. But here it suddenly switches to middle alignment?

[dmachaj]

Not sure about this one. I tried setting ReferenceAlignment: Left and it still adds the space.

[dmachaj]

I think the templated T is what confuses it. I see many examples of changes in this PR where var & i is correctly adjusted to be var& i. So this is not universally wrong. There are just a small number of false positive type matches.