ci: prevent build OOM by throttling locationd concurrency (#1527)

* ci: add conditional swap creation to prebuilt workflow

- Dynamically creates an 8GB swap file on systems with less than 8GB RAM.
- Ensures builds complete reliably on low-memory environments.
- Introduced cleanup step to remove swap after workflow execution.

* Nice save

* clean

* reduce swap size in prebuilt workflow
- Adjusted swap file size from 8GB to 4GB to optimize resource usage.

* remove swap creation from prebuilt workflow
- Simplified workflow by removing dynamic swap file creation and cleanup.
- Adjusted resource management to rely on existing system resources.

* update sunnypilot build workflow to use explicit script calls

- Replaced `op` commands with explicit `/data/openpilot/tools/op.sh` script calls for better reliability and clarity.

* update sunnypilot build workflow to use systemd for process management

- Replaced `/data/openpilot/tools/op.sh` script calls with `systemctl` commands for improved compatibility and reliability.
- Ensures consistent resource management during start and stop operations.

* Splitting a bit the build then?

* split build steps in sunnypilot prebuilt workflow

- Added separate build steps for `modeld`, `modeld_v2`, and `locationd` with descriptive messages.
- Improves logging and clarity during the build process.

* limit locationd parallel processes aiming to help with resource consumption

* typo

* adding op's location d AND bumping to 4 cores for them

* Apply suggestion from @sunnyhaibin

---------

Co-authored-by: Jason Wen <haibin.wen3@gmail.com>

.github/workflows/sunnypilot-build-prebuilt.yaml

@@ -180,6 +180,15 @@ jobs:
           ./release/release_files.py | sort | uniq | rsync -rRl${RUNNER_DEBUG:+v} --files-from=- . $BUILD_DIR/
           cd $BUILD_DIR
           sed -i '/from .board.jungle import PandaJungle, PandaJungleDFU/s/^/#/' panda/__init__.py
+          echo "Building sunnypilot's modeld..."
+          scons -j$(nproc) cache_dir=${{env.SCONS_CACHE_DIR}} --minimal sunnypilot/modeld
+          echo "Building sunnypilot's modeld_v2..."
+          scons -j$(nproc) cache_dir=${{env.SCONS_CACHE_DIR}} --minimal sunnypilot/modeld_v2
+          echo "Building sunnypilot's locationd..."
+          scons -j4 cache_dir=${{env.SCONS_CACHE_DIR}} --minimal sunnypilot/selfdrive/locationd
+          echo "Building openpilot's locationd..."
+          scons -j4 cache_dir=${{env.SCONS_CACHE_DIR}} --minimal selfdrive/locationd
+          echo "Building rest of sunnypilot"
           scons -j$(nproc) cache_dir=${{env.SCONS_CACHE_DIR}} --minimal
           touch ${BUILD_DIR}/prebuilt
           if [[ "${{ runner.debug }}" == "1" ]]; then