🔧 Add selective image rebuild flags and enhance R dependency scanning

- Added --rebuild-builder, -student, hub flags to start-jupyterhub.sh for granular Docker rebuilds
- Updated check_if_image_needs_rebuild to accept per-image force flag and propagate no-cache option
- Added libuv1-dev dependency in Dockerfile.builder (likely for quarto or R runtime)
- Rewrote install_quarto_deps.R to:
a) Manually parse library()/require() and remotes::install_git/github calls
b) Distinguish between quarto-required packages (must reside in persistent target_lib)
c), CRAN and git/github dependencies
d) Install with robust error handling, skipping unavailable packages
- Removed dependency on attachment package for scanning

obijupyterhub/Dockerfile.builder

@@ -32,6 +32,7 @@ RUN apt-get update \
        libpng-dev \
        libtiff5-dev \
        libjpeg-dev \
+       libuv1-dev \
     && apt-get clean \
     && rm -rf /var/lib/apt/lists/*