explicitly set Boost_DIR in DependencyInstaller

[openroad-ci]

Description

This PR fixes a build failure where CMake could not locate the system-installed Boost configuration (BoostConfig.cmake), even though Boost 1.89.0 was successfully installed.

Changes

• Added -save-deps-prefixes=/etc/openroad_deps_prefixes.txt parameter when calling DependencyInstaller.sh in Dockerfile for dev target. Then for the builder target we check if the file /etc/openroad_deps_prefixes.txt exists and use it for the cmake build command.
• Updated etc/DependencyInstaller.sh to explicitly set Boost_DIR in the generated openroad_deps_prefixes.txt.
• The script now detects the correct Boost CMake configuration directory (checking both lib/cmake/Boost-* and lib64/cmake/Boost-*) and passes this path to CMake.

Reason

• We weren't passing the correct dependency prefixes txt file to our build knows exactly where are the dependencies it needs to build it, thus not getting confused on which cmake config files it should use too.
• In some environments (such as Docker containers), setting Boost_ROOT is insufficient for find_package(Boost CONFIG) to locate the configuration files. Explicitly setting Boost_DIR ensures CMake can find the installed Boost package.

[github-actions]

clang-tidy review says "All clean, LGTM! 👍"

[gemini-code-assist]

Code Review

This pull request effectively addresses the build failure by explicitly setting Boost_DIR in etc/DependencyInstaller.sh. The logic correctly identifies the Boost CMake configuration directory and passes it to CMake, enhancing the robustness of the dependency installation process. The use of realpath ensures canonical paths are used, which is a good practice. The changes are well-implemented and directly resolve the described issue.

[github-actions]

clang-tidy review says "All clean, LGTM! 👍"