[bgfx] Add new port

[Outurnate]

Rewrite of #9163

I've only written a port for bgfx. There's no way to get GENie to use the artifacts from another port (i.e. bx or bimg), so I saw little point in exposing them

There was a bug in vcpkg_build_make as well - the docs specified that there was a TARGET parameter where no such parameter existed. I added this parameter, as well as two others to override the target for debug/release builds

[JackBoosY]

Seems have problem:

make: *** No rule to make target 'vs2017-debug32'.  Stop.

[Outurnate]

A couple more changes in vcpkg_build_make. I added a new WORKING_DIRECTORY option. I removed the section that closes gpg-agent.exe on Windows since it doesn't work (the code was copy/pasted from the icu port - it still had a ref to a variable that was only in the original port). It seemed unnecessary since the process is a part of Msys2 and in no way prevents the build from completing

As it turns out, the windows make target for the project is sort of broken. The makefile just calls devenv PATH_TO_SLN /Build which ends up just launching Visual Studio. I used the makefile to generate the SLN file, then ran msbuild over that

[JackBoosY]

/azp run

[JackBoosY]

Only have windows build failure, please download failure log here and resolve them.

Thanks.

[Outurnate]

There's nothing in any of those log bundles. I tested this port on the Windows 10 dev VM provided by Microsoft

[JackBoosY]

@Outurnate I will provide your failure logs tomorrow.

[JackBoosY]

@Outurnate I think you catch a vcpkg bug: #9729.

[JackBoosY]

Could you remove it and replace it to VCPKG_TARGET_EXECUTABLE_SUFFIX?

[LilyWangL]

@Outurnate Can you address the review suggestions? Thanks!

[nyalloc]

Would be really eager to see this library added to vcpkg.

[JackBoosY]

Closing this PR since it seems that no progress is being made. Please reopen if work is still being done.