ci/windows-docker: Move rustup install into a ps1 script

We will need this in order to be able to add conditionals
depending on the rustc version, like we do on the linux
script.

Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer-rs/-/merge_requests/1506>

ci/windows-docker/Dockerfile

@@ -13,10 +13,8 @@ RUN choco install -y pkgconfiglite nasm llvm openssl
 RUN setx PATH '%PATH%;C:\Program Files\NASM;C:\gst-install\bin'
 ENV PKG_CONFIG_PATH="C:\gst-install\lib\pkgconfig"
 
-COPY install_gst.ps1 install_dav1d.ps1 C:\
+COPY install_gst.ps1 install_dav1d.ps1 install_rust.ps1 install_cargo_utils.ps1 C:\
 RUN C:\install_gst.ps1
 RUN C:\install_dav1d.ps1
-
-RUN Invoke-WebRequest -Uri https://win.rustup.rs/x86_64 -OutFile C:\rustup-init.exe
-RUN C:\rustup-init.exe -y --profile minimal --default-toolchain $env:RUST_VERSION
-RUN cargo install --locked cargo-c --version 0.9.22+cargo-0.72
+RUN C:\install_rust.ps1
+RUN C:\install_cargo_utils.ps1

ci/windows-docker/install_cargo_utils.ps1

@@ -0,0 +1,14 @@
+[Net.ServicePointManager]::SecurityProtocol = [Net.SecurityProtocolType]::Tls12;
+
+rustup --version
+rustc --version
+cargo --version
+
+cargo install --locked cargo-c --version 0.9.26+cargo-0.72
+
+if (!$?) {
+  Write-Host "Failed to install cargo-c"
+  Exit 1
+}
+
+cargo-cbuild --version

ci/windows-docker/install_rust.ps1

@@ -0,0 +1,17 @@
+[Net.ServicePointManager]::SecurityProtocol = [Net.SecurityProtocolType]::Tls12;
+
+$rustup_url = 'https://win.rustup.rs/x86_64'
+
+Invoke-WebRequest -Uri $rustup_url -OutFile C:\rustup-init.exe
+
+if (!$?) {
+  Write-Host "Failed to download rustup"
+  Exit 1
+}
+
+C:\rustup-init.exe -y --profile minimal --default-toolchain $env:RUST_VERSION
+
+if (!$?) {
+  Write-Host "Failed to install rust"
+  Exit 1
+}