fix(ci): install the R packages pipelines use instead of relying on the image

bincraft v5.5.1 dropped lubridate, dplyr, purrr, data.table and others from
its imports, so the pipelines' own calls now depend on whatever the build-env
image's site library or the shared R_LIBS_USER cache happens to hold. The arm64
redhat:9 image has no progressr under R 4.4.3, which fails every
process-cran-updates-redhat-9-arm64 run since v5.5.1.

- Install progressr and lubridate for process-updates, which call them inline.
- Install purrr for packages-to-build.R and data.table for the weekly audit.
- Drop the unused dplyr and progressr library() calls from packages-to-build.R.
- Install RPostgres in every pipeline that talks to the metadata DB, since
  bincraft silently skips the DB (and the per-minor index aborts) without it.
- Reinstall bincraft in the prune re-index step, whose /tmp library does not
  survive from the prune step.

.crow/backfill-flat-safety.yaml

@@ -155,6 +155,7 @@ steps:
       - git clone -q https://pat-s:$$REPO_RO_TOKEN@git.devxy.io/devxy/build-cran-binaries.git .
       - mkdir -p /tmp/R-pkgs
       - /opt/R/$R_VERSION/bin/Rscript local/install-bincraft.R
+      - UVR_R_BIN=/opt/R/$R_VERSION/bin/R local/uvr-install.sh RPostgres
       - |
         set -eu
         LIMIT=""