Some updates to attempt to optimize our Dockerfile (#4417)

Successfully built locally, now to see if CI passes

## Motivation and Context
<!--- Why is this change required? What problem does it solve? -->
<!--- If it fixes an open issue, please link to the issue here -->
CI for PRs from forks has been [failing on Acquire Build
Image](https://github.com/smithy-lang/smithy-rs/actions/runs/19682977713/job/56381464286?pr=4394)
with error:
```
Saving base image for use in later jobs...
write /home/runner/work/smithy-rs/smithy-rs/.docker_temp_1730454122: no space left on device
```
The image build would succeed, but the task would fail when saving the
built image locally.

## Description
<!--- Describe your changes in detail -->

Attempted to slim down the Dockerfile, but only managed to knock off
~30MB (out of 1.8GB), so not much luck there. Was able to create more
room by adding a new action that does:
```
run: |
  sudo rm -rf /usr/share/dotnet
  sudo rm -rf "$AGENT_TOOLSDIRECTORY"
``` 
and deletes some of the included tools we don't use. In my testing this
freed up ~5GB which should be enough to allow builds to succeed.

----

_By submitting this pull request, I confirm that you can use, modify,
copy, and redistribute this contribution, under the terms of your
choice._

Author: landonxjames

.github/actions/free-disk-space/action.yml

@@ -0,0 +1,13 @@
+# Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
+# SPDX-License-Identifier: Apache-2.0
+
+name: 'Free Disk Space'
+description: 'Free up disk space on GitHub Actions runners'
+runs:
+  using: 'composite'
+  steps:
+    - name: Free up disk space
+      shell: bash
+      run: |
+        sudo rm -rf /usr/share/dotnet
+        sudo rm -rf "$AGENT_TOOLSDIRECTORY"

.github/workflows/ci-main.yml

@@ -36,6 +36,7 @@ jobs:
     - uses: GitHubSecurityLab/actions-permissions/monitor@v1
     - name: Checkout
       uses: actions/checkout@v4
+    - uses: ./.github/actions/free-disk-space
     - name: Acquire credentials
       uses: aws-actions/configure-aws-credentials@v4
       with:

.github/workflows/ci-pr-forks.yml

@@ -34,6 +34,7 @@ jobs:
     - uses: actions/checkout@v4
       with:
         path: smithy-rs
+    - uses: ./smithy-rs/.github/actions/free-disk-space
     - name: Acquire base image
       id: acquire
       env:

.github/workflows/ci-pr.yml

@@ -69,6 +69,7 @@ jobs:
     - uses: actions/checkout@v4
       with:
         path: smithy-rs
+    - uses: ./smithy-rs/.github/actions/free-disk-space
     - name: Acquire base image
       id: acquire
       env:

tools/ci-build/.dockerignore

@@ -0,0 +1,5 @@
+target/
+*.md
+.github/
+design/
+examples/

tools/ci-build/Dockerfile

@@ -120,7 +120,8 @@ RUN cargo install --locked --path tools/ci-build/changelogger && \
     cargo install --locked --path tools/ci-build/sdk-versioner && \
     chmod g+rw -R /opt/cargo/registry && \
     rm -rf /opt/cargo/registry/src && \
-    rm -rf /opt/cargo/git/db
+    rm -rf /opt/cargo/git/db && \
+    rm -rf /root/.cargo/registry/cache
 
 FROM install_rust AS cargo_tools
 ARG cargo_deny_version=0.16.4
@@ -149,7 +150,8 @@ RUN cargo install cargo-deny --locked --version ${cargo_deny_version} && \
     cargo install mdbook --locked --version ${cargo_mdbook_version} && \
     cargo install mdbook-mermaid --locked --version ${cargo_mdbook_mermaid_version} && \
     rm -rf /opt/cargo/registry/src && \
-    rm -rf /opt/cargo/git/db
+    rm -rf /opt/cargo/git/db && \
+    rm -rf /root/.cargo/registry/cache
 
 # nodejs needed by internal release process
 FROM install_rust AS nodejs
@@ -196,6 +198,7 @@ RUN set -eux; \
         bc \
         ca-certificates \
         clang \
+        cmake \
         gcc \
         git \
         glibc-langpack-en \
@@ -209,7 +212,6 @@ RUN set -eux; \
         python3-devel \
         python3-pip \
         shadow-utils \
-        cmake \
         tar \
         unzip && \
     yum clean all && \
@@ -226,19 +228,8 @@ RUN set -eux; \
 
 COPY --chown=build:build --from=local_tools /opt/cargo /opt/cargo
 COPY --chown=build:build --from=gradle_wrapper /opt/gradle /home/build/.gradle
-COPY --chown=build:build --from=cargo_tools /opt/cargo/bin/cargo-deny /opt/cargo/bin/cargo-deny
-COPY --chown=build:build --from=cargo_tools /opt/cargo/bin/cargo-udeps /opt/cargo/bin/cargo-udeps
-COPY --chown=build:build --from=cargo_tools /opt/cargo/bin/cargo-hack /opt/cargo/bin/cargo-hack
-COPY --chown=build:build --from=cargo_tools /opt/cargo/bin/cargo-minimal-versions /opt/cargo/bin/cargo-minimal-versions
-COPY --chown=build:build --from=cargo_tools /opt/cargo/bin/cargo-check-external-types /opt/cargo/bin/cargo-check-external-types
-COPY --chown=build:build --from=cargo_tools /opt/cargo/bin/maturin /opt/cargo/bin/maturin
-COPY --chown=build:build --from=cargo_tools /opt/cargo/bin/wasm-pack /opt/cargo/bin/wasm-pack
-COPY --chown=build:build --from=cargo_tools /opt/cargo/bin/wasmtime /opt/cargo/bin/wasmtime
-COPY --chown=build:build --from=cargo_tools /opt/cargo/bin/cargo-component /opt/cargo/bin/cargo-component
+COPY --chown=build:build --from=cargo_tools /opt/cargo/bin/ /opt/cargo/bin/
 COPY --chown=build:build --from=install_rust /opt/rustup /opt/rustup
-COPY --chown=build:build --from=cargo_tools /opt/cargo/bin/cargo-semver-checks /opt/cargo/bin/cargo-semver-checks
-COPY --chown=build:build --from=cargo_tools /opt/cargo/bin/mdbook /opt/cargo/bin/mdbook
-COPY --chown=build:build --from=cargo_tools /opt/cargo/bin/mdbook-mermaid /opt/cargo/bin/mdbook-mermaid
 COPY --chown=build:build --from=nodejs /opt/nodejs /opt/nodejs
 COPY --chown=build:build --from=musl_toolchain /usr/local/musl/ /usr/local/musl/
 ENV PATH=/opt/nodejs/bin:/opt/cargo/bin:$PATH:/usr/local/musl/bin/ \