[vcpkg baseline][libmicrohttpd] Control dependencies, doc, examples, test

[dg0yt]

• What does your PR fix?

  • Fixes [libmicrohttpd] Port doesn't declare its dependencies #17636 by explicitly
    • disabling https (was inactive on Windows; was used randomly when libgnutls happened to be found in the system; has issues when linking the static build of port libgnutls, [libgnutls] Static use depends on -ldl, not carried in pc file #17650)
    • disabling curl (used for tests)
    • declaring gettext dependency (if not windows)
  • Disables building of doc and examples (common practice in vcpkg)
  • Adds mingw support

• Which triplets are supported/not supported? Have you updated the CI baseline?

  unchanged, no
  Note that CI baseline contains: libmicrohttpd:x64-windows-static-md=fail

• Does your PR follow the maintainer guide?

  yes

• If you have added/updated a port: Have you run ./vcpkg x-add-version --all and committed the result?

  yes

CC @NancyLi1013

[dg0yt]

PS: A https feature might be added later, even for Windows (https://stackoverflow.com/questions/39928579/libmicrohttpd-and-ssl). Note that this feature limits licensing to "LGPL". Without https, licensing is "LGPL or eCos".

[dg0yt]

Converted version-string to version now.

[NancyLi1013]

LGTM, thanks for your PR @dg0yt.

[JackBoosY]

Ping @dan-shaw @strega-nil-ms for review and merge this PR first.

[dg0yt]

FTR, I also noticed a missing vcpkg_fixup_pkgconfig. The prefix is the installed dir, absolutely.
However, I cannot add the missing call before #17898 is merged.

[JackBoosY]

@dg0yt It doesn't matter, we can add it in other PRs

[dg0yt]

Reminder: The microhttpd build issue affects all changes to vcpkg_configure_make on osx. And these CI runs are expensive.