dev-python/pip can probably be removed

[bartoldeman]

This was added because of Reframe being installed seperately.
EESSI/compatibility-layer#72
However since sys-cluster/reframe was added later there is no more need for pip.

Removing pip from the compat layer is a great push to get users to load a Python module instead of pip installing things with the compat layer python.

[boegel]

With the changes in easybuilders/easybuild-easyblocks#2805, EasyBuild v4.6.2 and newer will prefer using pip install (over setup.py install) to install EasyBuild, so keeping pip in the compat layer probably makes sense.
Without it, we would need to use setup.py install instead, and that's a deprecated installation mechanism in recent versions of setuptools (and it actually seems broken too)

[bedroge]

This is only required for installing EasyBuild itself, right (other Python packages can use the pip from a EB-provided Python?)? In that case we may not need it anyway, since we also have pip in our build container.

pip does pull in quite a few dependencies (though they're all (small) Python libraries):

[ebuild  N     ] dev-python/msgpack-1.1.0::gentoo  USE="native-extensions -debug -test" PYTHON_TARGETS="python3_12 -pypy3 -python3_10 -python3_11 -python3_13" 164 KiB
[ebuild  N     ] dev-python/distlib-0.3.9::gentoo  USE="-test" PYTHON_TARGETS="python3_12 -pypy3 -python3_10 -python3_11 -python3_13" 1216 KiB
[ebuild  N     ] dev-python/distro-1.9.0::gentoo  USE="-test" PYTHON_TARGETS="python3_12 -pypy3 -python3_10 -python3_11 -python3_13" 60 KiB
[ebuild  N     ] dev-python/pyproject-hooks-1.2.0::gentoo  USE="-test" PYTHON_TARGETS="python3_12 -pypy3 -python3_10 -python3_11 -python3_13 -python3_13t" 19 KiB
[ebuild  N     ] dev-python/resolvelib-1.1.0::gentoo  USE="-test" PYTHON_TARGETS="python3_12 -pypy3 -python3_10 -python3_11 -python3_13" 755 KiB
[ebuild  N     ] dev-python/truststore-0.10.0::gentoo  USE="-test" PYTHON_TARGETS="python3_12 -pypy3 -python3_10 -python3_11 -python3_13" 28 KiB
[ebuild  N     ] dev-python/typing-extensions-4.12.2::gentoo  USE="-test" PYTHON_TARGETS="python3_12 -pypy3 -python3_10 -python3_11 -python3_13 -python3_13t" 84 KiB
[ebuild  N     ] dev-python/certifi-3024.7.22::gentoo  USE="-test" PYTHON_TARGETS="python3_12 -pypy3 -python3_10 -python3_11 -python3_13" 13 KiB
[ebuild  N     ] dev-python/charset-normalizer-3.4.0::gentoo  USE="-test" PYTHON_TARGETS="python3_12 -pypy3 -python3_10 -python3_11 -python3_13" 105 KiB
[ebuild  N     ] dev-python/pysocks-1.7.1-r2::gentoo  PYTHON_TARGETS="python3_12 -pypy3 -python3_10 -python3_11 -python3_13" 278 KiB
[ebuild  N     ] dev-python/urllib3-2.2.3::gentoo  USE="-brotli -http2 -test -zstd" PYTHON_TARGETS="python3_12 -pypy3 -python3_10 -python3_11 -python3_13" 294 KiB
[ebuild  N     ] dev-python/requests-2.32.3::gentoo  USE="(test-rust) -socks5 -test" PYTHON_TARGETS="python3_12 -pypy3 -python3_10 -python3_11 -python3_13" 129 KiB
[ebuild  N     ] dev-python/cachecontrol-0.14.1::gentoo  USE="-test" PYTHON_TARGETS="python3_12 -pypy3 -python3_10 -python3_11 -python3_13" 29 KiB
[ebuild  N     ] dev-python/pip-24.3.1-r2::gentoo  USE="(test-rust) -test" PYTHON_TARGETS="python3_12 -pypy3 -python3_10 -python3_11 -python3_13" 8984 KiB

[boegel]

pip may also be required for ReFrame?

Anyway, if we have pip in our build container, there should be no need to have it in the compat layer.

Though, people may be annoyed if the "system Python" doesn't have support for pip...