Feature Request: Build only backend libraries with Meson

Greetings,

Reading the build/install documentation using Meson (
https://www.postgresql.org/docs/current/install-meson.html) it's clear
there are a few target options to be used, but none of them offer an option
for a minimal build only including libraries, but not client executables.

Context: When packaging PostgreSQL in package managers (e.g., Conan), most
users are only interested in using libraries, but not executables. Building
that configuration will not only result in a smaller and faster build, but
also will require fewer external dependencies.

For now, the Meson build provides a unified way to build PostgreSQL on all
platforms by reusing the same build script, which is great when comparing
using autotools and Visual Studio in separate steps.

To conclude, I would like to bring into discussion a new target for Meson
build, like *backend-libs*, where only libraries are built (e.g.
libpq, libpgtypes, libecpg_compat, libecpg), resulting in a faster and
smaller build that can benefit package managers and developers.

Regards!