Consider making CI bazel cache public for read only access

Bazel allows you to use the build cache in a read-only manner see here. It would be very helpful for local builds if we could make the cache used by the CI available in read only mode for local builds, and potentially automatically set that up (via a bazelrc or maven profile). Currently building from scratch takes several hours for me, which is quite a pain. It would require changing the permissions on the GCP bucket though and I'm not sure if that's something we can do.

cc @karllessard

先阅读 issue 中链接的 Bazel 远程缓存文档，然后检查仓库的 CI 配置以及任何 bazelrc 或 Maven profile。确定 GCP bucket 是否可以安全地为本地构建提供只读访问权限，以及应如何配置该访问权限。完成的标准是：本地构建可以使用 CI 缓存，同时不需要写入权限，也不会危及该 bucket。