gitlab-ci, build/windows: Separate (again) Debian and Crossroad deps

Despite the good intentions, 4f965557 makes Debian contributors who
follows gimp-web-devel instructions to download more deps than needed
and makes unclear what are the crossroad deps. Let's fix it.

.gitlab-ci.yml

@@ -152,21 +152,16 @@ image-debian-x64:
     - echo "FROM debian:bookworm" > Dockerfile
     - echo "RUN apt-get update" >> Dockerfile
     - echo "RUN apt-get install -y --no-install-recommends \\" >> Dockerfile
-    # libjxl uses C++ features that require posix threads so we install
-    # specifically g++-mingw-w64-x86-64-posix and gcc-mingw-w64-x86-64-posix.
-    # Note that we can't install both the -posix and -win32 versions since
-    # update gcc-mingw-w64 (25). This is for crossroad builds only
-    - echo "appstream
+    # 'ca-certificates' is NOT a gimp dep, it is installed only to our Docker image work
+    - echo "ca-certificates
+            appstream
             at-spi2-core
             build-essential
             ccache
             clang
             lld
-            cpio
             desktop-file-utils
             ffmpeg
-            g++-mingw-w64-x86-64-posix
-            gcc-mingw-w64-x86-64-posix
             gettext
             ghostscript
             gi-docgen
@@ -219,12 +214,7 @@ image-debian-x64:
             mypaint-brushes
             poppler-data
             python3
-            python3-distutils
-            python3-docutils
             python3-gi
-            python3-pip
-            python3-zstandard
-            rpm
             valac
             xauth
             xsltproc

build/windows/1_build-deps-crossroad.sh

@@ -21,8 +21,24 @@ fi
 
 ## Install crossroad and its deps
 if [ "$GITLAB_CI" ]; then
-  apt-get install -y --no-install-recommends \
-                     wine                    \
+  apt-get update -y
+  # libjxl uses C++ features that require posix threads so we install
+  # specifically g++-mingw-w64-x86-64-posix and gcc-mingw-w64-x86-64-posix.
+  # Note that we can't install both the -posix and -win32 versions since
+  # update gcc-mingw-w64 (25).
+  apt-get install -y --no-install-recommends    \
+                     git                        \
+                     ccache                     \
+                     cpio                       \
+                     g++-mingw-w64-x86-64-posix \
+                     gcc-mingw-w64-x86-64-posix \
+                     meson                      \
+                     pkg-config                 \
+	                   python3-distutils          \
+                     python3-docutils           \
+                     python3-zstandard          \
+                     rpm                        \
+                     wine                       \
                      wine64
 fi
 git clone --depth $GIT_DEPTH https://gitlab.freedesktop.org/crossroad/crossroad