* [vcpkg] Add initial JSON support

This adds a JSON parser, as well as the amount of unicode support
required for JSON parsing to work according to the specification. In the
future, I hope to rewrite our existing XML files into JSON.

Additionally, as a drive-by, we've added the following:

* add /wd4800 to pragmas.h -- this is a "performance warning", for when
  you implicitly convert pointers or integers to bool, and shouldn't be
  an issue for us.
* Switched Parse::ParserBase to read unicode (as utf-8), as opposed to
  ASCII
* Building again under VCPKG_DEVELOPMENT_WARNINGS, yay!

This command takes a list of ports, and causes the final state of the
installed directory to be as-if one ran the install on an empty
installed directory (removing any unnecessary packages).

This is especially useful with the new `--x-install-root` option, which
allows one to set the `installed` directory for vcpkg to use.

Additionally, as a drive-by, we do some `stdfs` clean-up and add a
`.is_feature()` member function to BinaryParagraph (as opposed to
checking for `.feature().empty()`, which is far less clear to read).

This feature is experimental.

There are quite a few changes to the CMake build system packaged up into
one set here:
* Added `toolsrc/cmake/utilities.cmake`, which contains the following:
  * `vcpkg_detect_compiler` -- get the name of the C++ compiler, as one
    of {gcc, clang, msvc}
  * `vcpkg_detect_standard_library` -- get the name of the standard
    library we're linking to, as one of {libstdc++, libc++, msvc-stl}
  * `vcpkg_detect_std_filesystem` -- figure out how to link and call
    into C++17's filesystem; whether one needs to link to `stdc++fs` or
    `c++fs`, and whether to use `<filesystem>` or
    `<experimental/filesystem>`.
* Added a `VCPKG_WARNINGS_AS_ERRORS`, split off from
  `VCPKG_DEVELOPMENT_WARNINGS`, which allows one to use the development
  warnings without passing -Werror
* Rename `DEFINE_DISABLE_METRICS` to `VCPKG_DISABLE_METRICS` -- the
  former will now print a deprecation message and set the latter.
* Now, print a deprecation message on `WERROR`; it doesn't do anything
  since the behavior it requested is now the default.
* Pass `-std=c++17` if the compiler allows it, instead of `-std=c++1z`
* Do some code movement
* Pass `USE_STD_FILESYSTEM` if possible, instead of only on minGW
  * Renamed to `VCPKG_USE_STD_FILESYSTEM`

Additionally, we now pass `/W4` in Debug mode on x86 in the Visual
Studio build system; this brings it in line with the CMake build system,
and the x64 Visual Studio build system.

And finally, we make some minor code changes to support compiling in
VCPKG_DEVELOPMENT_WARNINGS mode.

* New policy: SKIP_DLL_ARCHITECTURE_CHECK.
The check only works if MS link.exe is used
otherwise the second linker member is missing
(according to the observed errors)

* rename to VCPKG_POLICY_SKIP_ARCHITECTURE_CHECK
since the dll check was ok but the lib check was failing.

* fix indentation

* move the if to a better position.

The old check checked to see if the computer was in developer mode _OR_ allowed sideloading apps, but we want _only_ developer mode.

* [vcpkg] Correct UInt128 code 😇

`UInt128::operator<<(x, y)` should clear the bottom 64 bits of `x` if
`y >= 64`; however, we don't do this, and so we duplicate `x`'s bottom
bits into `x.top` instead of moving them. Similarly, we have the
opposite problem for `UInt128::operator>>`. This commit fixes these
latent bugs, which we weren't hitting because the thing we use them for
never actually shifts more than 64 bits.

* added android triplets

* added android support to vcpkg

* added export directories to git ignore

* fix libraries naming

* added vckpg sources to visual studio project files

* rename file location

* issue with std::string fs:path copy initialization

* format path on VStudio

* fix checks format cannot work on fs::path

* support header only libraries

* support using architecture instead of triplets

* added prefab support

* added debug logs and prefab debug flag

* added support for empty packages i.e openssl

* [vcpkg] Fix spec instance name

* Change cub version for testing the changes

* Add vulkan-hpp to test

* vcpkg_from_git: Add support for git over ssh

* vcpkg_from_git: append ssh bin directory to path

* vcpkg_from_git: fix function signature on non windows platforms

* Revert "vcpkg_from_git: fix function signature on non windows platforms"

This reverts commit 0d608ee5911d2ba274e782a21dfe77a502a39053.

* Revert "vcpkg_from_git: append ssh bin directory to path"

This reverts commit 377ce3fae1e2c085a5da7ace8185624a345a511b.

* Partial Revert "vcpkg_from_git: Add support for git over ssh"

This partially reverts commit 9b81b16c4ccd3d8646d97e66234566a07af8a308.

Co-authored-by: Marc Boucek <marc.boucek@native-instruments.de>
Co-authored-by: Marc Boucek <marc.boucek@posteo.net>

* Add VCPKG_LOAD_VCVARS_ENV
allow loading vcvars.bat if an external toolchain file is used.

* add documentation