Add uv to our docker CI images

[kennyweiss]

PR #1936 adds support for installing Axom's Python interface/bindings through uv.

Since uv is not currently part of our docker images, we currently pip-install it every time.

Instead, we should add uv to the docker images by adding the following to our dockerfiles (e.g. right after setting up doxygen):

# Install uv, used to build/install/test Axom's Python wheel (src/python).
# Copied from the official image rather than pip-installed since Ubuntu's Python is PEP 668 "externally managed" could cause pip install to fail 
# Install to /usr/local/bin (not ~/.local/bin) because CI runs this image as root with HOME overridden, so a per-user install would not be on PATH.
# Use a pinned version and bump deliberately.
COPY --from=ghcr.io/astral-sh/uv:0.12.1@sha256:cf4eedcaa81655197f625739489effcbe71b61ceb1506f332c3facae5deceded /uv /uvx /usr/local/bin/
RUN uv --version