CXX-2973 add pkg-config test coverage using pkgconf

[eramongodb]

Resolves CXX-2973 by using pkgconf (obtained via uv tool) on Windows distros as followup to #1536.

Per pkgconf docs:

pkgconf is a program which helps to configure compiler and linker flags for development libraries. It is a superset of the functionality provided by pkg-config from freedesktop.org, but does not provide bug-compatibility with the original pkg-config.

and per Wikipedia:

default (instead of pkg-config) on linux and BSD distributions from many vendors, including Alpine Linux, Arch Linux, CentOS 8+, Debian, Fedora, FreeBSD, Mageia 7+, Manjaro and NetBSD.

The pkgconf project is actively maintained, with its latest release being 2.5.1 on June 2025. In contrast, the PyPI package for pkg-config has not been updated since July 2021. The pkg-config project itself has not seen any activity since January 2021, with the last stable release being 0.29.2 on March 2017. Therefore, this PR proposes adopting pkgconf as successor to pkg-config.

Following #1428, the pkgconf application can be easily obtained using uv tool install via install-build-tools.sh. Note the pkgconf package also provides a pkg-config binary alongside the pkgconf binary. Therefore, existing calls to pkg-config do not need to be changed.